Full span control surfaces... use spoilerons instead of flaperons. Deflecting them upward instead of down kills lift... you use elevator to hold the nose up and the plane will sink about like a heavy warbird that doesn't have flaps.

Don't go overboard on the spoiler throw... 5 deg is a lot. Put it on a switch that can change the mix eliminating the spoiler function. Then you have the knob to dial in the amount desired... and can flip a switch to put the plane back to normal aileron mode.

Practice with them at altitude to get the "feel' for what happens.

You can play with the Flaperons the same way and youwill quickly see why they are a bad idea... Every stall will depart into a spin with flaps down. If you know its comming and have the switch to kill the flaps... you can save it. (given adequate altitude...)