Hi,
I can't help in the Saito department as I fly mine electric.
I guess my question is when you snap from upright or when you snap from inverted, is the rotation in the same direction for both ?
Or do you snap one way form upright and then the other from inverted.
The rotation speed will vary based on the prop rotation.
My planes snap faster going left than they do going right. The motor torque and rotation helps going left but pushes against going right.
As for the knifeedge spin. Can't say for sure, but I think Bipes are harder to knifedge spin than monowings.
I can't help much there either as I can't knifeedge spin with either very well myself [&o]