strobe lighting and large family shot

I have to take a large family shot (25-30 people) next weekend. I have never taken a group shot this big before, and am feeling the heat. The shot will be taken indoors in a gymnasium, and there are risers available for the family to sit on. I am thinking I will have to go 3 rows deep. I have 2 Studio MaxIII lights (320), with umbrellas, and 1 background light. I also will be using my Canon 30D and the Canon 17-55mm lense. I have been researching this forum and am still unsure of how exactly to set up my lights. I hate to ask a question already posted, but can't seem to find an exact answer... so hoping for a bit of help and advice here... Thanks.

No one has any ideas? Hmmm, thought perhaps I might get some pointers.

If you're unsure, the best approach is to keep it simple.
I've seen planty of photographers just use one light directly above the camera for group shots. The light will be a bit flat, but you'll get all the faces exposed reasonably well without shadow problems.

The problem I can foresee using a single light is the folks further from the camera being underexposed compared to the ones in the forefround. You might be OK with a single light if you keep the depth of the group fairly shallow and bounce the light off a not-too-high ceiling or a fabricated bounce surface above the groups heads.

When I did a group of about 40 to 50 a little while back, I actually used six AlienBees lights with 60" umbrellas. I bounced some of the light off the cathedral ceiling (the group was near a wall and under the shorter dimension of the ceiling). Some of the lights were over ten feet from the floor. I used a handheld light meter in many different positions to ensure I had even lighting over the whole group. My camera was on a mount that I fabricated (using plywood, a center column from a tripod, and a clamp, with a 488RC2 ball head on top), about 18 inches above an eight-foot stepladder, looking down on the group. It worked out quite well.

I was wondering if I could set two lights beside the camera, and if that would help light up both sides of the group. And I was thinking I should have both lights taller then the group as well, reflecting down of course.