Not sure I understand the idea? It locks to the bar and glass for use?? If you are replacing bulbs, parts, screws, Everything, wouldn't the glass be OFF? Might be a cool idea if it extended to the glass Rails so it could be slide up and down the playfield while stripping parts or servicing instead of setting tools on the playfield? What do you service with the glass on and your tools on the glass? The coin door?

Better yet!! Make the tray the SAME width as a standard playfield glass and use the glass channels to support AND guide for the caddy! Now you would have my interest!!!!