RE: Got my LT-40 completed
G'day I have Kadet Seniors which were designed as three channel planes (no aileron) and an LT 40.
I would not fly the LT-40 as a three channel plane.
It does not have the dihedral of the Kadet Senior which is what makes the Senior such a good three channel plane.
The LT flies fine as designed.
Prop for a two stroke 46? I would start with an 11 x 6 or if it floats too much on landing 11 x 5. They do tend to float which is what makes them good trainers. They can fly very very slowly if needed.
As it is a trainer, I would probably use a Master Airscrew K series prop (the older ones) as they are tougher and more likely to survive a prop strike. APC seem to be more fragile though they do work better but this is a trainer and absolute power is not really a consideration but longevity and reliability are.
Mine has an extremely elderly Saito 45 Mk II which has the high lift cam from a 56. It flies it really well. I think I am using an 11.5 x 5 Bolly prop. (When you get too many planes, it can be hard to remember!)