What causes the plane to snap in a turn? Too tight a turn and and too little airspeed?
Also could you explain how you modified the wings to bolt to the inside of the fuselage vs the stock way the small screws were originally designed to hold the wings in place. You mentioned almost losing a wing this way, so I assume that you have modified this.

Are you still using the control throws you mentioned earlier, ie, 1/2 the recommended deflection in the manual for initial flights for your low rate, and the recommended initial throws for your high rate?

Enjoy your comments on assemblying and flying this plane.