I have ordered another receiver that has SBUS capabilities, and that may be the answer
I predict that it will be the source of more problems rather than providing the answer.
When I needed to extend the pulse width of an RC channel beyond what the transmitter setup provided I used this
yawDuration = pulseIn(yawInPin, HIGH);
yawDuration = map(yawDuration, 1000, 1800, 980, 2020);