A player is planning to play a £1000 tournament and is selling action at 1.2. Lets say its a 100 player tournament and the prize pool is distributed as follows:

1st 30%
2nd 18%
3rd 12%
4th 8.85%
5th 6.65%
6th 5.5%
7th 4.5%
8th 3.5%
9th 2.75%
10th 2.25%
11th 2%
12th 2%
13th 2%

My idea is to buy at spot rate and if the player cashes, pay juice on the winnings rather than at the start of the tournament. Possibly paying more juice for finishing in the higher positions. 

Is there a way of working out a fair 'juice structure' if they are worth the 1.2 that they say they are?