I assume you mean draftboard? I’m using Baltic birch plywood. There are other threads about painting draftboard if you hunt around on the forum.
As for using paint in this sort of thing, see my other mandala threads, I get into it there.
https://community.glowforge.com/search?q=%40evansd2%20in%3Afirst%20mandala%20order%3Alatest_topic
I mask using the same stuff I always do: