As Art was about to discuss the stab.

I designed the stab with 3/8" material for the spars with no sheeting top or bottom. Under flight loads the elevator was not very responsive and in checking it out on the ground with full up elevator
the stab was twisting which seemed to be negating the elevator response. The stab has a 39" span and there are no brace wires.
Remember the full scale had a flying tail so it would not be subject to this twisting effect.

On my new build I have sheeted the top and bottom of the stab and elevators and the stab is now rock solid. I have added 1/8"x1/4" cap strips where the ribs are to maintain
the scale look of the stab and elevators.

The rudder was very effective and will not need any changes.

On another note I fly my 1/3 scale Super Cub, which has the same airfoil, with differential on the ailerons. Lots of up aileron and very little down aileron.
The rudder is also mixed with the ailerons at 20% which helps the tail to track through turns much better.

With these adjustments and some further flight testing, on calmer days, it can be trimmed out to be a gentle flyer but also a responsive flyer that will be fun to fly.

Larry