Being a big guy, I hate the power index. I am sure there is a good formula to compare lifters, but just the straight Total/BW sucks for me. I believe it is better to compare lifters of the same bodyweight and not worry with comparison between body weights. You can however have a team competition that equally distributes points among various disciplines. I have used these in the past.
Power Clean Max-Mix
Broad Jump-Can be a mix if you have athletic lineman
Backwards Shot Put Throw-Mix
When Clay and I were at Alexander, our quarterback won the Shot put throw. At Troup, I had an undersized TE that blew everybody away in the Tire Flip. By doing it this way, we were able to have a good mix of linemen and skill kids in our top 10. At Troup, we even went so far as to have a Top 5 in Linemen, and a Top 5 in Skill and gave a trophy for the winner in both.