Good illustration.

Would you think that in a case such as this, that it would be OK to place the stock aileron horns facing backward, so that both were on the upper side of the wings... ideally hanging back to provide enough clearance for the control wire?

To minimize how strange this may look, the horns could be cut down to the lowest holes.

I'm working on a small 29" electric all wood Ultimate Biplane where this may be the only way to get enough structural support for anything.