My aileron balancing:
http://www.rynoth.com/wordpress/waiex/2 ... -ailerons/These were the aerobatic ailerons, which don't go level like the standard ailerons, I was simply trying to match them while removing as little material as possible for maximum counterweight. Turns out, I did a good job cutting the lead block and removed no lead whatsoever to achieve a matched result. I stuck a hinge pin in and used loops of kite string to attach them to ratchet straps to tune in level.
In my plane, the counterweights do indeed contact the bottom skin and end up being the limit on my aileron deflection, which I tend to prefer versus a stop somewhere else in the control system (i.e. max available deflection is possible.) I imagine while actually flying I will very rarely be at max deflection, especially with the extra roll authority of the aerobatic ailerons. The contact with the skin has a fairly large contact area though (the whole counterweight appears to contact the skin at the same time) and so far denting the lower skin while on the ground playing with the controls does not appear to be an issue. Upper skin contact is unlikely since the opposite aileron will contact the lower skin first, providing a stop.