Skip the rail tape. It not only looks awful, it only protects your board where it's been applied. Since your paddle is the most likely source of the dings, put something on the edges. Many people use a little padding and electrical tape. I went with the Surfco paddle guard: it works, is descrete, doesn't mark my board as easily as waterloged electrical tape and, after a year+ of use, it still looks as clean as the day I put it on.