So here's an idea:
Offer :
1) To pay a programmer $xyz per hour, to be paid if terminated short of the destiny.
And to pay that much at some specific payday when the success of the project can be measured.
State what success means and how to measure.
2) Pay the programmer along the way with a way to capitalize on your already profitable judgement.
In other words, special access to your signals and help leveraging that value.
3) Some subsistence along the way...so that, depending on the programmers current financials, s/he can survive a year or two of no other income.
All by contract that includes a stipulation that if the performance of you trading calls falls below some threshhold, the programmer is free to stop development. Then depending on how long the development is stopped, the programmer is free to leave with full wages or some kind of payment plan.