In every airplane I have had two aileron servos I have set up flaperons. Again, in every application it has always helped and never created a tip stall problem which again I don't think is possible due to the aerodynamics of the situation. When you deploy flaps you change the shape of the airfoil to one that develops more lift (as well as drag). The pressure under the wing becomes greater. What CAN happen though is that the ailerons will be less effective so plan for that and don't deploy them too much.

Right now I have a Venus 40, a somethin' extra and a spacewalker II and they are all set up for this and it works great for all of them.

Have fun - mix the flaps with the elevator for even more fun.