To the higher powers, I have a question, actually a few:

Suppose a friend, let's say Jill, wants to invest in another's ability, let's call him Jack.

Jill can lend Jack 14% more of his bankroll... ie she could give Jack $1k to add to a $7k bankroll. But, Jill is shrewd and risk averse, and she wants an as close to fixed return as possible. Jack calculates that Jill's contributions will add 20% of additional profit to his expected hourly return. He tells Jill, after I have played for 15hrs, I will pay you 105% of what you have loaned me ($1050) while he plans on making near $150 from Jill's loan. Is this a good deal for Jack? Should he pay out less or more? Should the time constraint be increased? I don't know how to assess paying out fixed returns on variable profits... If Jill wants to know the chance she will not be paid back her money, is that the same risk of Jack seeing his bankroll drop to $1k? Should Jack place a limit on how much investors can loan?

Jack could counter offer with the following: I will pay out 75% of whatever your added loaned funds contribute to my profits. Therefore, Jill's money follows along with Jack's. What is the better option for Jack?