Reflexing both ailerons will increase drag and help bleed off excess speed. However, reflex also reduces the maximum coefficient of lift which increases the stall speed. When the stall speed is increased so is the landing speed for a given stall margin. Lowering both ailerons (just like lowering flaps) will increase the maximum lift coefficient available and lower the stalling speed allowing a slower landing speed. As you lower the landing speed, you also lower the aileron control authority and increase adverse yaw. So, make sure that you have excess rudder and aileron control authority at slow speed berfore trying to lower both ailerons. Lower the ailerons in small increments at a safe altitude and check for control authority and tip stall tendencies to see if you can get the desired results without undesirable consequences. If tip stall is a problem you may have to resort to seperate flaps and ailerons.