JohnW, I don't think that P-factor is particularly significant. Given its druthers, even a trike model will slew left -- & that absolutely is not P-factor. With a trike, during take-off, P-factor only appears at rotation & then only briefly. With a tail dragger, it is present while the AC accelerates with its tail down -- right up to the point when it lifts its tail -- no more P-factor until rotation -- and again only briefly.

In high power, low speed, high Alpha situations (particularly with a large dia prop), P-factor appears again. However, I don't use right thrust in my models, & high-Alpha left turns just aren't a real problem until essentially at stall (if at all), then torque & spiral slipstream become the big players.

I just dont buy P-factor as a serious problem in model flight. With a full scale Corsair or Thunderbolt -- yes I'll accept it, but with a 40-size model trainer -- nope.