Here's another idea to get even lighting with 2 rows of 50 people. I have never tried it so this is just an idea, not sure if it will work.
Use the lights you have to light just enough people so that they are all properly lighted (lets say 2 rows of 10 people or 20 etc) then move the lights to the right and set up another 2 rows of 10 people or 20 and take a shot. Keep doing this until you have all 100 people then stitch the photos. If you don't want it to look like a panorama, take shots vertically as well. Just an idea that popped in my head. May or may not work. Don't bash me lol...