Writing Shadowrun Missions Options

[PenCapBlue]

I'm a fairly new to Shadowrun. I began as a player, and after that campaign fell apart with half the team joining the army or moving to Texas, we decided to start a new campaign. This time I'm the GM. We've had 2 runs (over 3 sessions), all very fun and successful. I have used the runs from the SR overlords, and find that they're a bit lacking. Maybe it's just my ability as GM, but...

Well, I started writing a run. It's straightforward. Mr Johnson wants a rival killed, which allows him to obtain a large sum of money. However this rival is a very nice guy that has done nothing wrong. Mostly a moral choice.

It will end with A.) the runners siding with Mr Johnson, and getting screwed out of most of their money (after a nasty fight), and notoriety or B.) them siding with the rival getting comparatively more money and getting jumped by Mr Johnson and his thugs.

Seems all fine and dandy, but I am new to this whole thing, and I have a sneaking suspicion that this run will fall short. I don't want a 12 hour run, and I don't want a 2 hour run. 4 hours seems about the right amount of time.

So the run is basically:
1.) meet Johnson
2.) Legwork
3.) find rival
4.) moral decision
5.) wrap it up after a fight.

I can send the text that I have written out. Any input? Advice? Experience? Should I just use a different pre made run (I do have a good one ready, which will be next if I use this one this coming Saturday)?

Thank you, any input is appreciated.