I am trying to see if I have some rules and concepts down, and have chosen an absurd example to illustrate it. I do not think this is really a question, just me trying to understand it. So if you see any glaring errors or notice something I did wrong please tell me.

Meet Chip. Chip is a simple magician of an nameless possession-based tradition. He is fairly competent at his relevant skills and attributes (3-4).
Chip likes to cook, and so he decides to try and make a living at making delicious fresh-baked treats to sell at his local Stuffer Shack. He decides to make "Chip's Chocolate Chipolicious Cookies".
Since their is no Cooking active skill, I will lump it into Artisan (just to illustrate). So Chip has artisan at 4 as well as his linked attribute (8 dice pool). I am the GM decide that baking a batch of cookies, assuming you have the needed materials, is a simple extended skill test, say Artisan+Logic (IIRC) (2, 30 minutes) (again this is just an example). Chip's oven can hold two batches at once.
So Chip just cashes in his dice pool and can make 2 batches at the same time.

Chip needs to get them into the two local stores before 12am, so he starts work at 8am and make two dozen for each store.
Everything is peachy for the first few days, but he starts to get sick of cleaning up and such during and after working.

So chip does what any demented Culinaromancer from a possession-based tradition would do.
In Phase one, he just needs an extra hand or two, or four. He goes to his local talisman and has a number of fully-articulated doll-like vessals made. He then summons a few watchers (1-4, his Charisma is a 4) in the morning to possess those dolls and do simple tasks in the kitchen while he works. As he still only owns a single oven, he is not making an additional cookies, nor asking his somewhat dull watchers to do much more than scrub dishes and move things around for him. As the gm I might decide that he could mix large batches of cookie dough and that the watcher could be trusted to spoon it onto a pan and place it in the oven, provived Chip was their to oversee them and nothing too unexpected happened.

So Chip's cookies get more popular, and other Stuffer Shacks nearby as well as a few Coffee Houses would like to sell them.
Chip goes ahead and buys a new place that has a few extra ovens (say 4 altogether). I am the gm say that he can now make 8 batches at a time, provided he is acting as an overseer as well for his small army of watchers.

The problem for Chip is that sales are not as good as he was hoping for. A friend suggests branching out a bit. Try some other types of cookies. He needs to experiment a bit.

I as the gm decides the watchers are of minimal value for this task. They can still run a mixer and shove stuff in an oven, but they are hopeless at following a recipe and experimenting.

So Chip takes the next step on his cooking journey. He buys a larger version of a doll vessel and summons a Task spirit to posses the doll (I assume that counts as a service). He then asks it to flip through a few recipe books and "try something new". It is using a skill on it summoner's behalf, so I assume that is an additional serve. That way Chip can still make his cookie-quota with his watcher assistants while his Task Spirit cooks some other things on its own. The Task Spirit is a Force 4, so the cookies are generally as good as if Chip had made them himself.

Occasionally, if there is a seasonal special, Chip might Bind the Task spirit for a bit. (Using the some old rules as a guideline, I would imagine each Service owed would be one day of servitude). When the spirit is Bound, Chip might whistle up another Task Spirit to assist giving him 2, or more, depending on how many he binds (up to a maximum of 4 bound and 1 summoned). Basically Chip can power-bake cookies limited only by the amount of oven he has on hand.

Time passes, and Chip is asked for even more business. So now chip chooses to bind the task spirit for the long term. Using the patrolling example, I would thing forcing the Task Spirit to posses a doll and cook for 24 hours a day wouldn't be that much different. So he does and pays the Karma...as many times with as many spirits as he wants. Creating a karmically-costly army of enslaved spirits making his thrice-damned cookies.

Am I thinking along the correct lines here? I know that with cookies it seems weird but not harmless, but lets say I was making them use a chip encoder to copy BTL's I wrote. Or working as physical labour on my farm. Or using any Technical Skill the summoner summoned them with.

On a similar note. Let say I have channeling, can I bind long term a spirit that I use to posses me for battle? How would that work?

Keep in mind:
a) Capital for investment
b) Taxes, or at least bribes, shakedown, or hired protection
c) Wouldn't you rather be shadowrunning?
d) Unfriendly competition

It looks good on paper as long as Cookiemonster leads a charmed life. One batch of anthrax-cookies and the big C is back in the shadows. That's not even counting the increasing chance of rolling a glitch and having to deal with a rogue Task spirit or the like.

I also figure the Health Department might have some issues.
"Do these dolls have Food Handling Permits? How do you sterilize them?"
Of course, the cookies were just an example. You could do this with any Artisan or Technical skill.

i don't think i would let you long-term bind a spirit for battle.

long-term binding a task spirit to use it's skill for you for a year would be acceptable, imo, and i can't say that it really bothers me in the slightest (again, provided it's a fairly straightforward assignment. fixing cars that come into a mechanic shop would be fine with me. travelling around and stealing cars requires a lot more decision-making on the spirit's part, so i would say no (unless you're willing to accept that the spirit will simply steal the nearest car, then the next-nearest, etc, and will drive them all to the same location, with no attempts to conceal the theft, or escape pursuit).

Did anyone else, when big crow was talking about all the spirits running the shop, start to hear the faeries from cinderella singing while they're making that huge cake and dress and whatnot? "Bippity Bopity Boo!" I think 40 hours without sleep may be making me a tad loopy.

or the brooms from Mickey Mouse's "Sorcerer's Apprentice" in Fantasia.

I actually thought dwarves coming back from mining singing Hi Ho Hi Ho...but that may just be my anti-dwarve racism coming through...

Also, why did we all got right to Disney films? Damn subliminal conditioning...

I don't think anyone has actually commented on your original query about rules interpretations, so I will.

I think everything looks fine and I'd allow all of that in my game, save for the long term binding of a spirit to combat channelling. And the reason for this is not actually game balance, but just that I don't think it's actually possible.

With long term binding, you tie a spirit to continue its last service for a year and a day. In my game, a service of possess me for some unspecified purpose is not a service. You would say "possess me and kill those enemies," "possess me and save my friends from drowning," etc. Yes, Channelling lets you guide the spirit whilst possessed, but I wouldn't let that overrule the basic principle of things.

In addition to that, I think the mental stress of channelling a spirit for an entire year would destroy the magician's mind. I don't see channelling as changing possession from being ridden and controlled by another intelligence to pick up spirit powers with no baggage. It lets you tweak things, it lets you impose some of your own personality on the possessing spirit. You'd still be sharing your head with another entity for 366 days. I mean what would happen when you slept?

Apart from that last, all is good. And I particularly like the example too. "Chip's Chocolate Chipolicious Cookies." Heh!

Correct me if I'm wrong here, but:

Possession Traditions replace the Materialization power with possession.
Watchers can manifest not materialize.
Therefore, Watchers of a possession tradition cannot possess since they never had materialization to begin with to trade for possession?

... And then Chips goes crazy and has his little minions kidnap the neighbors to make into his cookies. Runners are hired to investigate and find the horror of Chip's kitchen as they fend off the skittering dolls wielding knives. In the end, Chip is killed and his dolls are eventually buried with him. Years later, there are disappearances in the same neighborhood and the runners find the dolls are missing in Chip's grave...

Possession doesn't take a service either to point out something you said in the original post. So summoning the Task and telling it to possess the vessel doesn't cost a service. Making a new type of cookie does.

actually, as i understand it, commanding the spirit to posess something *does* count as a task.