Sorry, Jim, but you can't blame the forum membership for not being able to answer your very specific question. We just don't have the answer. Sometimes you have to be the first to provide one.
Most taillights will not cover the holes. But if you get creative you can cover them. Currently the plate is mounted above the holes, you can drill the back plate and mount it below the holes to cover up some of them. Here is my current setup....
Here is a doc I created about what you are trying to cover http://webpages.charter.net/v0lusia/RearFenderHoles.pdf
Thanks.... I painted it at a local high school. I took a bring your own project autobody class.
Here is another shot from this winter..... It looks black when not in the sun, in the sun the green flake coat really pops.....