Mrs. Batman,
Welcome to the family.
Sorry about your hubs condition. I don't have much to say about the stimulator except what you already stated. Sometimes it works and sometimes it don't.
My neurologist is talking about maybe having me tested for one if my pain can't be controlled by meds.
In my case I'm complicated with degenerative cerebral atrophy and the RSD has spread to the spinal area of the cerebellum.
I hope the best for him and let us know how it goes...

P.S.: Congrates on the new one