I think the following split sounds fair:
70/30 + Stake Back for ITM
60/40 + Stake Back for FT
50/50 + Stake Back for a Win

using these terms. horse is gonna play 5.50 300GTD at 8pm est. also had horse escrow 2k points for insurance in case he runs off. win and run i keep the pts. win n ship i ship points back. lose i ship points back