Most of the horrible weird looking relic jobs are done on polyurethane finished guitars. It just doesn’t work. A full nitro guitar with practice you can get it done like the pros. It just takes practice. I’ve done all kinds of relics, worn parts, faded finishes, checking, etc. All really good results but it’s way to easy to go overboard. Someone said leave it to the pros. We’ll have did the pros figure it out? Probably a lot of trial and error.