My luck with spray mounting has not been good. The corners tend to lift up over time. Permanent mounting spray holds better than the removable type. The problem with the permanent ones is if something goes wrong, you cannot undo it.

I would recommend Beva 371 liquid or something similar. If you have access to a heat mounting press, then any of the archival, removable mounting tissues will do the job but the press can have problems if your painting has thick passages.

I have a lot of large acrylic paintings done on Yupo, and I spent the better part of my life trying to find something to mount them to panel. On line,people say how they use gel medium – I could only ever get a temporary bond using it.
I finally ran across this, which works great -Locktite spray adhesive 200 High Performance Middleweight. It is also acid free.

SO something you might experiment with – paint the back of the paper with acrylic gesso. Then use the Locktite spray to attach it to the panel.

Thanks for that tip. I will have to try some. Yupo is likely one of the most glue repellent materials out there….good to know something keeps it in place.

Loctite 200 is way better. (home depot, lowes, hobby lobby, walmart etc.)
Spray back of your paper and the mounting board. Wait a full minute then carefully align, press down and then……use a print making brayer/roller and roll the paper and board “sandwich” down. You can put on a sheet of clean scrap paper while you roll to keep artwork clean. It is the rolling with brayer that really binds the art to the board.