Thanks for doing this thread. Congrats on making such a cool and great looking project. It should more accurately be called a working piece of art! I've been thinking about doing a re-theme for quite a while and reading this thread is giving me the inspiration to actually try it (maybe). I already have a few trashed playfields for potential candidates. I haven't decided which technique I'd use for the playfield art though.
Some different techniques I've though about include:
1) hand paint art directly onto the playfield then clear coat it
2) paint background color(s) on playfield then use multiple assorted water slide decals or stickers
3) paint playfield white then reverse print art on a clear mylar and stick it on playfield
4) paint white on areas of playfield with white art, print full playfield art on clear vinyl overlay,
stick printed overlay on playfield, then put on a playfield sized sheet of polycarbonate to protect
Looks like you with method 4? Was the final clear PC layer just peel and stick on top of the overlay? How did you handle non-flat areas of the playfield, like the trough or kick out hole. I'm assuming the kick out hole would slight edge from the PC overlay? Did you have to add anything to the edge to make a smooth transition or was the PC thin enough where its not an issue?
I and any other potential custom brew or re-themer's out there would love to hear you advice after doing this yourself.