mgnostic

I would suggest the HS 82mg or HS85MG. The recommendation is not so much for more torque (A few more ounces of torque won't hurt though) but for the more robust gear train in the same size package. The HS81 has enough torque to move the ailerons but it is pretty easy to strip the gears just by handling the wing. I would measure the thickness of the wing and if there was enough room I would even go with an HS225 if it will fit. Alternatively, everybody poops on bell cranks these days but they aren't that bad if they are well built. The trick is to assemble the linkage with ball links throughout to prevent (well minimize) any slop. The SE5a is never going to be a pattern plane and a lot of your roll input is going to involve the rudder.