A simple two part jig that holds 100mm slate coasters so the piece's height in the F1 is the same up or down as the rubber feet should fit in the gaps in the lower plate. No glue needed as both plates fit in F1 baseplate space. Cut out of 3mm colour acrylic on a P2 (not black as the F1 can damage that)
Remove F1 baseplate
place LOWER plate in the baseplate space of the F1
Place TOP plate on top of the lower plate, ensure they're both flush in the baseplate hole
place a 100mm coaster face up in the jig, rotate until all the rubber pads are in the void left for them
focus your F1 with the Focus Knob or in XCS.
You only have to do this once as when you turn the slate coaster later it will be at the same height!
Connect the F1 in side the XCS software
set a 100mm circle in XCS, place it in the centre of the XCS screen, (blue cross hairs will confirm placement), select in Framing Options OUTLINE, and test the framing
Select the 100mm circle, turn Output OFF
Select the 100mm circle again, Arrange it to Back
Select the 100mm circle again, and LOCK it
place elements in the mask and engrave them as many times as you like on as many slate coasters