I had a hardened B17 bought off Ebay. I didn't do any hydrating, I just washed it with saddle soap, let it dry, then did a light coat of Proofide on the top and heavier on th bottom. I left in the sun for an afternoon, and it was greatly improved. This was enough to let my discover that the sit bone areas collapsed under my weight, leaving the hatchet effect. The (I told my buyer about it) buyer did not complain. I have a B17 Imp that is pretty decent.

As many stories as exist about the success of alternatives to Proofide, stories exist about their failures, up to destroying a good saddle.