Alternative investor risk levels.

investment bracket:
2%
1.5%
1%
0.5%
0.25%
0.1%

the max bet is a function of the combined amounts invested under each bracket.

so if 100 bitcoin invested at 1% and 100 bitcoin invested at 0.5% the max profit will be 0.75%

either win/lose scenario:
100 bitcoin bet. win = 75 bitcoin to 1% investors and 0.25% to 0.5% investors. Of course lose its a negative instead

Dooglus, this might be better than changing the house edge, because then you leave the investors to make their choice.