It's hard to say. Because when you use flaps, you're most certainly flying slower than when ailerons are obviously effective. And when you fly slower, flaps or not, ailerons really are less effective.

One thing that is for sure.......... when you're flying slowly, you really don't want to use too much aileron if you have an alternative. Get the wing up near stall AOA and a little aileron deflection brings on the stall. And that stall is only on one side. The other side's aileron movement lessens the probability of a stall. And that gives you snap roll. It's almost always the cause of the dreaded "torque roll on takeoff" when the pilot slams the throttle, jerks the elevator and prays.... and tries to steer the plane back to the right with the ailerons.