Good luck archimeech, with the project and the healing. My wife had hip surgery recently and I guess joint surgery has came light years. My brother had rotator cuff surgery in the 90's and they literally almost killed him. He's a mess now, while my wife is doing better and better everyday.
I also have to thank you for lighting a fire under me to get my HF bench blast cab out of the shed and get it squared away. I'm not going to be going water blast (yet ) but am going to mod it and still run air.
This whole project reminds me of when I was working for a fruit farm/packer. They had a pull behind spray rig that the pump had been kapoot for years, but the rest of the rig was all stainless. I don't know squat about the engineering of it, but the pump was this rediculous little cast iron thing that they wanted like $3k for and in looking at the specs I didn't see why I couldn't use a similar volume vane pump that was like $150. It also had this rediculous multi belt drive system for the fan which could not be tensioned and I redesigned that too. Nothing fancy and just using plain logic and to the bosses surprise not only did it work good, it put out a finer spray than it had new. Which doesn't surprise me because all this stuff would get wet from the spray and with no tensioners on the fan belts I'm sure they slipped like crazy.
My point being, I think you are on to something and not everything is rocket science even though some companies want you to think so. And sometimes even rocket scientists are over thinking it
Thanks for sharing your progress.