Anyone have their backcanes shaped ?

My thighs are the limiting factor in my width, giving me an 18" wide cushion and frame, otherwise I'd probably be on a 17" or 16" wide chair.
Trying to get my rear wheels narrower, I have camber, my wheels are always rubbing against the back canes so I'm thinking of trying to get a bend in the back canes so where the back rest attaches it would be 16" or 17" wide instead of 18". Grabbing myself ane extra 1" or 2".

Anyone ever do this?

Apparently it gets done on power chairs ? I'm told they call it endomorphing (spelling) ? yet to find a reference on the intertubes. anyone know?