You might put one line parallel to the edge, right in the middle. I do most of my borders that way. It ends up looking fairly good. I use a bookmark as sort of a guide. I just put one side of the bookmark against the inner border seam and sew along the other side of the bookmark. When I get close to the end of the bookmark, I just move it down. I find that easier than the blue painter's tape.
Here's a picture of a recent quilt I did that way, in case it helps you decide what you want to do.
Dina