Programming Snap Ailerons on 9C
Shame you don't have a 9Z, you could, instead of a multipoint mix, simply use a "trigger mix" where the mix doesn't trigger until a certain point on the elevator stick. but 9C won't do this on any channel but throttle.
However, on 9C, you do need only one mix, with link ON, to get the flaperons to both respond. master is elevator, slave is flap, link ON.
Hope this is helpful.