Here is my proposed solution.
Sandbagging is dictated by money combined with people that try and game the system.
It seems to me like the payouts should go to:
1) The top 50 in the tournAment. If you finished in The top 100 then you should get something.
2). The players that have moved up the most ranking in wppr points. I would think that the biggest movers should get at least as much as the top 25. This rewards those that have done well and those that have improved the most. If it is your first tourney and you kick ass then that should be rewarded as well to keep you coming back.
The winners of B, C and D can get some hardware because coming on top in any tourney is tough but no guaranteed money because really they are the winners of the losers. Put the cash into the hands of those that have performed throughout the entire tourney and bias it a bit to those that are just getting into the competitive pinball scene.
In the end it is about growing the game. Just my two cents.