For reference, my Magnum XLS46 turns the APC 12x4 at 13,500 peak Typically set at 13,200 or 13,300 for flying with fantastic transition on my fuel and with this prop. Sounds like it is performing exactly in the ballpark of the better 46FX's.

Fuel: Wildcat 15% nitro/18% synthetic, with added 4% castor oil.
Glowplug: Fox Gold.
Muffler: stock Magnum with baffle removed.