Hi Guys,
using APC props for years I find that it's true that are efficient props for 3D they are too much heavy. This doesn't allow fast transition and causes rpm lost.
After several tests I've finally found really the BEST prop. Graupner, Eco Cam Prop (light grey, glass filled), or better Cam Prop (same design but carbon filled, so much more rigid).
My TT Pro 50 Hely, used on a Ripmax Extreme, turns the Cam Prop 12,6x4 at 13500 rpm on ground, on a 5% nitro fuel.
The 12,6x4 wheight is 30 grams, half than an APC 13x4 W!!!!
As I know that you can't find them in USA, If you want , you can find the full range of Cam Props on the Hollein site (it's a German even-online shop).
P.s. for me Master props are good only to mix epoxy.

Andrea