Ok, I've got a run going down on Sunday where the player group of 7 PCs with an NPC, a dozen elementals, at least 8 drones and a vehicle are taking on a couple dozen naga and 12 - 18 spirits. It's been building up to this point for weeks and the run's in tight quarters in an underground base.

So, any suggestions on how to keep at least the opponent's dice rolling smooth and the pace rolling?

I can do multiple sheets of results for a variety of different dice amounts, and I can abstract things. My concern about abstracting is them feeling like I'm dictating results rather than them winning or losing on their own merits.

Any suggestions?

With a sweep of his...

Hat

I don't like running large scale combat in shadowrun for exactly the reason you've dictated but an easy way to do it is to have npc's that aren't directly engaging the party, or in the case of spirits and the like acting on direct and specific orders, use "group actions", tallying the average relevant dice pool and rolling it once per group per action, and then applying the results in a way you see as acceptable. It isn't perfect, and you need to make sure to keep the groupings somewhat sensible and straightforward but it works more often than not in my games.

Turn one big fight into a lot of little fights. Rather than 20 on 60, have lots of little 5 on 2s. In tight quarters, the size of the party should keep them all from getting involved in every 2 second exchange of gunfire and magic. Once the players get into the rythmn of “ambush, 1.5 turns of combat, admin reload, assess injuries, resume movement”, you’ll find things getting a lot more fluid.

This is probably pretty obvious, but don't have multiple Spirit types, or at the very least, have the majority of the Spirits be the same type and feature the same powers so that most of the stats are uniform. It'll make for much easier book keeping since it becomes more a question of how many Spirits the PCs have taken out of the fight as opposed to which Spirits in particular. If you must have some variety on that end, just vary the Force levels a li'l bit-- due to the linearity, I find the the difference between a Force 3 and a Force 4's body is a lot easier to remember without notes than the attribute differences between Spirits of different types.

Delegate responsibiltiy of drones and spirit to the PC's in question. With whipstitch idea I ten to has groups of spirits of the same or similar force. I also tend to abstract dice rolls to average percentages in off screen rolls.
O and as you more then aware: Preperation

Know what your NPC's are going to do before you start so then you can move smoothly through the stratergy to the tactical level. You will also not necessarily have to micro manage as the player will not be able to follow everything that is going on.

"You fired a one a two plus two and followed by a one and one. So there are no bullets in that gun. Bang."

Here are a few things I do with large player groups:

Have one of your players track the initiative for you. Pick the person in the group who is typically the most distracted/distracting during combat, or who has the least to do in combat (Face, Hacker/TM). It is just one less thing you have to keep track of.

Only roll initiative once for each group of like NPCs. If all your Nagas are the same, roll once, and apply the initiative to all of the Nagas. If you are having one of your players track initiative for you, and you want to keep them in the dark on what they are facing, just give them generic group names like Mon1, Mon2, etc. You can even throw in a couple of extra non-existent Mon initiatives to keep them guessing.

Hand wave any purely NPC on NPC combat actions. Just do whatever sounds cool at the moment, and if you don't want the players to know you are hand waving, toss a bunch of dice around behind your screen and ignore the results.

One trick I have heard other GMs endorse, but do not use myself:

Make all of your NPC rolls ahead of time. Before the game starts, spend some time generating results from your NPCs primary combat pools. Then when you need a result from that pool, just grab a number from either end of the list (or a random number), and then mark that result off.

Thanks for the ideas so far. I've done the have a sheet of pre-rolled results ahead of time, but for a different system. The number of dice vary which makes things a bit more challenging here. I'd already standardized the naga and spirits to a large extent but may do a bit more of that. Prep is definitely going to be my friend. Part of the reason I'm asking the question now.

One thing I may also consider is using average # of hits for damage, resists, etc for most of the fights and roll them for either key fights or key moments. If I can resolve a combat quickly like that, it's helpful.

I didn't quite follow the group roll / average idea. Not sure if someone wants to say a bit more about that or not.

Thanks for the suggestions!

With a sweep of his...

Hat

Buy hits.

Every 4 dices in pool is 1 hit.

I would go the abstraction route. SR is not designed to handle large-scale combats, especially with lots of magic and matrix involvement. I would use the larger battle as a backdrop to build tension for smaller confrontations the PCs will take part in. Come up with some crucial objectives the team has to accomplish to turn the tide of battle- killing the main naga that conjured all the enemy spirits, or what have you. If they are doing well, have their affiliated spirits and drones come out on top. But if they falter, have the battle turn against their spirits and drones. If you focus all that combat where the players are (i.e.- where the game mechanics and dice rolling are needed), your game will bog down.

There are two ways you can go: focus on the strategy/tactics and switch to a wargame/boardgame approach or focus on the story and stick to the RPG approach. In the first case, I guess you'd better get some minis and get ready for an afternoon/night of boardgaming (you could even use another ruleset).

Here are my ideas for the RPG way:
* For NPC vs NPC combat, what I do is give each side a dice pool according to its size and threat rating. Then I just roll opposed tests and use the result to decide what happens without going too deep into details.
* For PC vs NPC, have the players do most of the work for you: give them the stats of your NPCs (at least, those you can share the stats without revealing anything) and let them take care of the rolling and just tell you the results.
* For NPC vs PC, it's a bit more complicated. When the NPC use guns, I just use a house rule based on the suppressive fire rule. But if they are spirits, it'll be a bit more complicated. If I were in your positions, I'd use the NPC vs NPC method to deal with the effectiveness of the PC's spirits and drones against the NPC and then focus on the action on the PCs.
Don't forget that you're not playing a wargame/boardgame but telling a story. Don't show/draw the situations to the players, tell them what their PC see and what happens to them.

What I would do for this is instead of having, say 4 spirits, is to have only the stats for 1 spirit that is pretty tough, BUT, describe the combat as if it were 4 spirits. You only need to worry about one set of stats, and when the condtion monitor reaches 3 boxes describe it as if the PC's killed off one of the spirits and then another when the CM reaches 6 boxes, etc. Saves you a lot of book work and your PC's probably won't know the difference.