Mark. It would be possible indeed to reduce the size of your ailerons, but the big limiter as I see it is going to be the aft spar. Unless you want to move it, I think you have to stick with the plane versions or you will suffer a reduced roll rate. If you did want to shift the aft spar, you could probably get away with reducing the length to 50% of the wing and increase the depth to 30% constant depth of the chord line. This should retain the existing roll rate and allow you to shorten the length of the aileron.
Cheers. Peter Bancks. stranged...@dodo.com.au http://www.homebuiltairplanes.com http://canardaviationforum.dmt.net