@nprofile1q... @nprofile1q... Neat, using an SLA printer for board exposure is something I should definitely try at
@nprofile1q... . Is this using standard PCB photoresist?
Back when I did home etching of PCBs I also got good results with persulfate, but what really helped a lot was agitating the solution (for evenness and decreased undercut, using an aquarium bubbler) and warming it up (for speed, using an aquarium heater). If you have issues with that, give it a shot if you haven't yet.
