In my opinion you’re just going to fight frustration with that plan.
In Inkscape, or your design tool of choice, place your coaster design inside an outline of your coaster. Make the outline its own color.
Place a piece of cardboard on the bed of your glowforge. Gently secure it so if you bump it slightly doing the next steps it won’t move.
In the GFUI set everything to ignore except the outlines of the coaster(s). Cut them and remove them from the cardboard. Place your coasters inside the outlines, set the outline cut to ignore and proceed. You can engrave coasters pretty much forever. If you want to do different designs, just use the first design as your template. Each file you load will be perfectly placed relative to your cardboard jig.
Presumably you will eventually lase something besides a coaster. At that point to make more coasters just get a new piece of cardboard.