Aileron differential uses???
This is one of those many areas that I think too much emphasis is put on, and yours is the perfect case-in-point.
Adverse yaw, in a model plane is, in most cases, so mimimal it hardly needs mentioning. But there are those who want everything to be perfect, but, as you stated, when the plane is inverted, so is your differential, so you're beyond "back to square one".