Since you don't need speed, an 11-4 is also an excellent choice for the .46 LA in a trainer -- it will give even more thrust than the 11-5 & let the engine wind up to ~13,000 -- close to its torque peak @ 12,700 & its power peak @ 13,400.

The 11-5, while much better than the 11-6, is still too much prop for that engine.