I use two different shape magnets, a bar and round, Amazon of course. I include the magnet positions on the cut line drawing but in a different color so that after framing the overall cut I have it lightly burn the magnet lines (usually dashes) and then I can add enough mags to flatten the sheet and keep things in place.
[https://www.amazon.com/dp/B09FSYF9C4/?tag=lstir-20]
These are thin enough that my diode housing passes over them so I can start my setup with 4 -8 mags that may get drawn over with the framing and the mag scoring but at the low power and high speed it hasn't hurt anything.
