My idea was to attach a couple flaps to the inboard underside of the wing but I assume the length of the ailerons where the flaps are would then be pretty much ineffective on the downswing but act like an airbrake on the upswing.
I have modified a trainer this way and yes it is better or easier to operate than flaperons. Yesterday or Saturday for the first time I flew with flapperons on another trainer. Flapperons give more of a slower approach than split flaps/ ailerons would, so to speak.
When using flapperons one needs to have experience with flying with the tail, then flapperons are a sinch to use when landing.
Back again, I just looked at this plane in HL and IMO this plane should sail in like a glider. No need for flaps
Good Luck.