Well I have decided on robarts. The 551rs retracts are the ones I am planning on. Since the wing has dihedral in it, I am using the 85 degree retracts so the gear when down is vertical. I am enjoying this build so much, after I am done, I think i will get the 1/5th scale mustang.
Anyone who has built or is building the 1/7 scale p51 feel free to chime in if you have any advice. I am working on finishing the wing now.