I did use an old rv6 aileron trim kit. I modified it by extending the arm so it extendedover the flaperon mechanism and it works nicely. The trim handle is under the flap handle though and is a little difficult to use but i plan on raising the handle and it should be easier.
The kit works exactly like the one did in my old rv6. Didn't even need any extra parts except a piece of flat mild steel to extend the arm under the handle. I just bolted it on with some #6 screws and nuts, but you could weld an extension on, too.