RE: Torque question
Torque follows a curve like horsepower, and usually peaks at lower rpm than the max power point.
Acceleration comes from thrust versus mass, thrust comes from power and the efficiency with which it is converted to thrust, and power is torque times rpm. Maximum acceleration potential is at maximum power rpm coupled to the optimum prop for the airspeed. Engine "A" may have more peak hp than engine "B" at the same peak rpm for both of let's say 16,000rpm. But, if engine "B" generates more torque at say 11,000 rpm than engine "A" does, then engine "B" can swing more prop load at 11k than engine "A" can, even though engine "A" can swing more prop at peak power rpm than engine "B". So if you prop them for 11,000 rpm at WOT with similar props, engine B will out accelerate engine A. If you prop them both for 16k at WOT, then engine A can out accelerate engine B assuming the prop choices in both cases are within reason.
If the roll gets worse at speed it is twist. If it worse at launch then it is side thrust. In an nutshell anyway. From experience a tiny bit of with-torque thrust offset can cause mayhem with higher power models with short wingspans - as in left thrust on regular tractor deltas. Aero and inertial damping is small. But roll tendenceies that change with speed are aero induced. You can have some of both which is a fair way to have fits.
MJD