A very good friend of mine like me to do some poster shots for his dance crew (20+ people). The location will be in a library. I am a complete beginner of flash lighting shooter. As I like to give my friend a hand and at same time I like to get my flash lighting photography going through this task. So, I really really need a lot of help from your experts.
What I have:
1 580EX II, 1 430EX, a reflector, 1 begon light stand, 1 reflector stand, 2 43" umbrella
Bottom line:
I am convinced all my investment in lighting gears so far will do little for this task. I might need to move on those Alien Bee strobe setting in order to get close to complete the project. And you can see that I have none of those and little knowledge how strobe works.
Questions:
1. If you were me, besides quitting, where will you start? what is the purchase you are going to make in order to make the shoot possible. I am saving up for a 200mm f/2, so the moderate investment (towards minimum budget) is preferable. Certainly those investment on gears should be as portable as possible and as re-usable as possible for my future development on lighting photography.
2. After recommending me the gear list, I really like to know how the set up will look like for a group of 20+. I appreciate if it can be as detail as possible...
3. Technically, I have no clue on strobes if that set up is recommended. i.e. how to trigger the strobes, using a PC cord, a canon flash... The alien bee website doesn't really give me much information on how to use their stuff, but i am open to lean though
Your input is absolutely priceless for a lighting newbie like me.
I thank you all in advance.

