I've tried APC 16X4-16x8-16.5X5 / XOAR 18x6 / Master Airscrew 16x8...basically, whatever was in the garage. The max rpm I got was with the 16x4 @ 8,900. The 16.5x5 gave the most thrust. Hovering was done just under full throttle and there was a teeny bit of pullout or none at all.

I've seen your vid. and it looks good, but I'm not geting those results. My engine is fully broken-in and running great. My dad wants to use it in a biplane, so that's the main reason I'm switching engines. The CRRC is only slightly heavier, but it puts out oodles more power.