I like about 50% on spoilerons rule of thumb and 30% on flapperons. I find spoilerons are much more forgiving than flapperons because you can have too much flap for a turn and end up snapping out. The spoilerons can be as much as you like, but I like to leave the last 50% of travel for aileron authority.

I use spoilerons a LOT in windy conditions as I find they really help me to keep the plane in front of me when I practice rollers (ie, TR's at an angle to the wind, so it looks stationary). They also help some of my planes KE spin easier.

I very seldom use flapperons unless I want to do very tight waterfalls.

I have both programmed into my JR 8103 "landing" switch -- up for spoilerons, neutral is off and down is flapperons.