mikes68charger
It would perhaps be more logical to use the outers as ailerons and the inners just as elevators.
As a flying wing rather than a delta the control surfaces are close to the CofG and particularly at speed small movements have a significant effect so it is unlikely you will all four surfaces as elevators. .
As elevons it might take some effort to eliminate any unwanted pitch change with aileron movement and vice versa. Keeping pitch and roll control on different surfaces should keep it simple to set up.