Only "problem" with having Brian Siders in the competition, is that he'll win no matter what.
Four weight classes though, I suppose they will be 90kg, 110 kg, 125kg, and 125kg+?
I think you could get away with three weight classes: 100kg, 125kg and 125kg+.
Repetitions with four plates (405 lbs) would probably be where BB's are able to perform the best.
With a repetition contest, it will be easier for the crowd to understand what is going on - not too much judging involved.
The contest would also be finished in a shorter period of time, making it more attractive and competitive in a full schedule like the O weekend.
YIP
Zack