I'd get to know the plane first with a 6 pitch prop. Learn to land it in the shortest distance. Get the CG dialed in that allows good stability, but also allows you to flare the plane right before touchdown. Flying an over weight plane with a 8 pitch prop really makes controlling the landing speed more of a job. If you fly in a small field, small runway your prop choices have to be based on your abilitys with that plane. If you fly at some huge paved area where you can afford to make 30 MPH touchdowns anywhere in any direction, then obviously your prop choices are just about how fast you want the engine to turn and what works best for the plane's aerodynamics.
I would guess that a 10x8 prop for a start for speed.