Another thing to consider. The sailpane and pylon racer would use the flaps momentarily in flight versus for large portions of the flight. The extra drag due to the flaps would be regained quickly after the turn. Even then the flap deflection would have to be very small to make it worth the trouble. I fly Quickees and all of the people I know do not use flap-elevator coupling, 500's or Q40's.

I gave up slope soaring after a near miss with a hang glider.

Also another thing to consider.....a lighter airplane does not mean that the Cl has to decrease. Lift is a function of the Cl and the velocity squared.