RE: How much pitch control would elevons provide
I was wrong about the swept wing.... this glider has TE taper and straight LE.
As to how a plane pitches with aileron up/down, I'll know fairly soon on how it does with this design. I'll likely finish construction today and if WX permits test tomorrow.
The config is full length elevons with them trimming down for up pitch. It will have as well an elevator (at least for testing) which can be switched in/out by mix switch.