I set up dual servers on my Nexstar and use the flaperon function often. Just flew it a little today, very little because of the @#$% wind, but I used the flaps in a full 100% down position and I actually could see a difference in the added lift, sooner lift offs and slower flybys. I found no need for retrimming for straite and level flight when I deploy them. I also have an "up" switch on my Hitec radio for this function so I use them as spoilers to! I have only used them on the ground and frankly the effect is neglagable, but cool looking non the less. Someday I will see what spoilers will do to my airspeed when I am at a safe altitude.

Oh, one more thing. Once you put one servo in each wing, check the wing's ballance!! I had to add a heafty fishing weigt inside the right wing because my plane kept dipping it's wing after the modification. I was supprised to because both serveos were exacly the same. Hmm, oh well. It's fine now.