I think the Darts look the best with a vinyl top. Mine was originally a vinyl top car but I removed it back in the 80's but it just didn't look right so now that I'm redoing the car, I'm going back to the original color with a vinyl top.
Just remember, a vinyl top can help hide a few imperfections but they won't hide everything, a lot will show through the vinyl. Also a dark color vinyl top will get hot in the sun light and any body work you do can start to come apart from the heat. You want very little filler or primer/paint between the top/glue and the sheet metal.