Vid, I just got my first machine, and I have been reading over your guides. Incredible work, and I commend you on being gracious enough to share this with everyone. My Firepower board isn't too bad at all, the only real wear that needs to have paint applied to it are the areas the the ball has worn down as a result of cupped or sunken inserts. At this point, it is nice enough that I don't want to pull everything and clear over the play field. I just want to make localized repair. I saw elsewhere someone uses either polycrylic or that other stuff that you recommended to "build up" the inserts and then sand them down. I'm scared to death of sanding them down...and the paint around it as well. I figured it might be easier to pull them out as per your guide, touch up the paint on the actual insert itself, and then coat the top of them with this leveling compound. After it had dried, I was hoping to use your method for leveling new inserts to fit to get it flat, and then re-install and glued it.
So the short question is: do you think this could work? Any downsides to it?
Here's an overview of the play field, you can see around the multiplier lights there are a few touchups that I need to do, but that overall it's not bad.