I did this on the Fathom Restore ;
http://aussiepinball.com/index.php?topic=6318.75Page 6, down the bottom.
I found this to be easy. Just use the airbrush with a friskit mask and take your time. I ended up using a matt clear and it blend it quite well. You could see the repaired area in the sun, or in a photo with the flash on. Looked 100 times better than the gaping hole !
It was very easy, but I would recommend it only in small areas.