I will only be using it when there are no more than three possible outcomes in an event. I've tried developing it myself but I'm struggling.

Once I have the basic formula I intend to extend it to cover possibilities that currently BetAngel doesn't eg, (1) specific outcomes for one or more teams and green the rest and (2) recognition that the market depth is not always adequate to fill the bets that BetAngel uses to green up.
If I can develop something useful, I will, of course, make it available to others to use.