I think the 'runners up' should be awarded the non-cash prizes that have been donated, on a highest gets the pick system (so first runnerup gets first choice; final runner up gets what is left).
#Top winners = #Entrants - #non-cash prizes
Split the cash between the Top winners.
I was kinda assuming that was in mind, but I thought it would be worth actually spelling out. If the number of entrants ends up being huge, then maybe consider a different approach.
DSP


