A 72 Firstly, Half-Elf isn't a subtype. Assuming you want a Half-Elf/Half-Centaur, strictly speaking only Humanoids gain subtypes that can be chosen (Except for Outsiders with the Race Builder, they're all assumed to be Native), so it's not possible as written.

Off-hand, though, I think any of the humanoid subtypes is probably worth 1 RP for unlocking other racial features.