I can hold a 45deg banked turn in my glider at ~55kts, and due to the span the outer tip is going some 33% faster than the inner one. It has always amazed me that there is very little, if any overbanking tendency; I suspect there are many other things at play, not limited to wing flex, fin/fuselage effects, rudder deflection, etc.
I agree with Locked Door about flying the output - apply control inputs to achieve your desired attitude...