Jerry,

The first thing I'd do it to hold the ailerons in place and move the stick or move them to full deflection, then push on them. I have a buddy, flying partner, who builds scale. He has this tendency to put in belcranks and all sorts of hidden control systems that may work well on the ground, but fail under air loads. He also tends to use inexpensive, low power servos. None of these are conducive to good roll control in flight.

I don't know about seaplanes and pendulum effect, but I do know that an 80 inch plane usually has ailerons large enough to require high power servos and a good, stiff 4-40 hook-up.