Got it! Thanks a ton WT! Overlay works now but it seems to draw a little fuzzier than it looks on my screen in Pixelmator...
Pixelmator mockup:
How it looks in Reaper:
Notice the right edge is noticeably thicker and the whole thing just looks fuzzier and uglier? Is this some sort of resolution issue on my end or something or is it just the way Reaper draws the images?