Light kits and first time use!

I have a 30D with a 580ex Flash,and that is what I have been using at some family weddings (as a friend gig). I just do some pretty normal shots and some formal shots too, but I would like to try a little more professional shots with better lights.

I bought an interfit 600 kit with umbrellas and stands. I am going to the church this evening to take some test shots with a few of my friends, and I would like to know the best set up??? The largest group will be 8-10 people. How far away do I put the stands from the people. I did some test shots in my basement with a pseudo background with another friend and they looked pretty good. I had the 580EX on MANUAL and the lights set up on full power. The camera was also on manual mode. Now I know that the 30D has a sync speed of 1/250, so I do not exceed that limit....I am shooting at aroun F-9ish....Am I speaking English, I will post a pic of my 580EX Flash shots in seddings, without the light set up...tell me what you think?

Here is a pic with just my 580 ex? Critique please, be nice I am not a professional...YET

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Sync speed is 1/125th for studio strobes. If you blast people with your strobes at full power the background will be black, or dark. You may have to use a lower power. There are two main options for light placement:
- One directly above you (or very slightly to one side), with one lighting the background.
- One to camera right as main, one to camera left as fill. 2:1 ratio, maybe. If you want even lighting on each person the strobe has to be a similar distance to each side of the line - ie have it 1 meter from the person on the right and 4 meters from the person on the left or you'll have uneven lighting.
- As an experiment, have one slightly to camera right, with a soft box at the group. Have another to camera left bouncing off the ceiling, no light modifier. It might work, it might not, but you should learn something.

With groups where some people are behind others beware of shadows on the face of the people at the back - that's why the easy way is one light over your head, it avoids the shadows. With a single row you can have more flexability.

Also beware of reflections from the background, on the rare occasion i've done formals inside the church it's been a pain. Also have an assistant to help assemble and disassemble things quickly.

ThanksTim..I will try that!