We powder in house. Recently we had a major issue with a bunch of PL1/4 x 5' x 12' sheets of 5052 that had been hung on the outside of a 19 story office building. About 60 sheets total, laser cut in a "artistic" pattern. Had some adhesion issues, and we needed to strip all the panels and do it again.
Our options were bead blast or recut. Probably 2.5 - 3 hrs to blast each panel. We found someone local that put them in an oven at 600 degrees and burnt the coating off in five minutes. Cost us $20 per panel.
Now we just needed to wash and recoat. I don't if that would be an option for you, but I can run down some info on what they do regularly. Maybe find someone local to you with a similar set up.
This is one of the reworked panels. The burn-off was clean - if you wanted to re-grain it would be quick work.
