Your missing the point of why we use the APC 12.25 x 3.75 prop on fun fly planes. It may not allow the .40 size engines like the .46 LA to reach there optimum power band for speed, but for hovering and 3d maneuvers it's the most prop you can get away with. You want massive air flow over your control surfaces (which gives you much better control at very slow air speeds) and great pull out torque. If you were to compare this props static pull on the ground with that of the 10 x 6 screaming at 14000 rpm, you would notice the 12" prop pulls way more even at that slower 11000 rpm .
Try it on that magic and you will never go back, just ignore the sound of the slower spinning engine.