The key to flaperons is to only use them on the final leg and wings level.
Also as you have done is setting up them proper amount of elevator is necessary too.

Critics of flaperons generally have failures because they are banking the plane with them deployed and don't know how to steer with the rudder.

I use them on a few of my planes and like yourself it is a hands off approach except for throttle.

I wish my Supra Fly had them but is a single aileron servo wing so she just eats up runway when landing.