Thanks! Because I was afraid of the thin paper buckling when it got wet, I didn’t thin the paint with water at all (soft acrylic tube paint) so there was no pooling either.

The problem I did run into was that the acrylic stays slightly tacky even when completely dry so spreads like this tended to stick together when closed. But I think I have solved that today by adding a layer of MATTE VARNISH once it’s done.