Clewis, I was at the same point. I had a bunch of winter harvested staves that were full of undulations. I've made bows leaving some cambium on but I really wanted a clean back. I used our hosty power washer figureing I had nothing to lose. It work great I posted a thread a while ago title removing Bark and cambium with power washer. I did something like 1 Elm and 19 HHB staves in 2 1/2 hours with backs that looked like summer harvested staves. Not sure if it'll work on all woods but great on HHB and Elm.
Bjrogg