I use APC 10.5x6, 11x5 and 11x6 on my .46 and .50 size 2-strokes. Right now they both have 10.5X6 on them.

Your preference will likely depend on your flying style. I started using the 10.5x6 in one plane because the 11" props "ticked" the ice when flying with skis. Liked it so much I stuck with it year-round.

May I point out that while the shallower pitch engines allow you to reduce the load on the engine and achieve higher RPM/torque, you also have reduced "bite" in the air. The 6" moves 17% farther through the air in 1 revolution than the 5". Variations in air temp, humidity, the plane-to-plane of total weight and "cleanness" of profile may give you more thrust with a higher pitch prop. And you, hopefully, ain't always flyin at full throttle. The braking effect of the larger props helps or hinders on slow downward maneuvers at low RPM.

Hook the plane up to a fish scale and see which prop pulls harder at full RPM.