Pilot DAR
if I can add something to this interesting topic ; I do not think that 'recent' GA aircraft suffers from lack of aileron authority ; this means that the 'upflow ' help effect on the 'good' wing is very secondary to the negative difference in asimmetry around the vertical axis (yaw) from the downgoing blade thrust (P factor) ; this need to be counteracted by rudder which authority is indeed more limiting in the engine-out conditions.
In other words, I am pretty sure that very seldom you will find problems in keeping the wings level also in an engine-out situation(whatever propeller roatation), as ailerons are generally sufficiently powerful to raise watever wing, and corresponding forces are not vey high.
Instead, you for sure will found 'difficulties' (both from authority and forces) in keeping the heading fixed in an engine-out condition, using rudder/pedal force.
Please keep the Flight Test Community updated on your new project.