Possible to reduce elevon throw for pitch but not roll?

I have a plane (Strix Nano Goblin) that is a “plank” design with elevons. By all accounts the throws need to be kept low when acting to control pitch (otherwise it goes into a hyperstall), but the throws can be higher when acting to control roll.

Is there a recommended way to represent this in ArduPlane? Or do I need to adjust PTCH_RATE_FF/PTCH2SRV_RMAX_UP/PTCH2SRV_RMAX_DN/PTCH2SRV_TCONST to control it indirectly?