1970 dart swinger tail stripe, help needed

They are waterslide right? the sides line up around the quarter lights and I believe the trunk isn't exactly "straight" more like a "boomerang" because of how the body and trunk lid is. I haven't done one but will when I get mine in paint. This is just what I know from research. This is in terms of the kits out there. if painting one on I would assume the same holds true ,you wouldn't mask it exactly straight it wont look right.