The hardest poart of the painting is the edges...they are one SPTA. When everything is painted and dry, I affix the cut panel to the backer, clamp and dry at leat 4 hours. Often, after unclamping, touch up painting is required, no matter how careful I was. I always seem to find some spot I missed or the worng color became exposed, etc.
For something like this plaque and my frames I use poly as a protective coat. In this case 3 coats of clear Gloss Spray Poly. I prefer wipe-on poly for my frames.
I do back, dry, flip and do front, dry, second coat, dry, filip, second coat onf back, dry, flip, very light sanding is any needed, third coat, dry. Add hanger on back. Finished.
BTW, things do look better in the photo. Close up and personel you can see many flaws.. but as often quoted in NY; "You will never see them from Brooklyn"!!!!