If you haven't already you might consider protecting the inside of the frame as well. Thoroughly coat the inside with a vegetable based oil such as boiled linseed oil, Boeshield or WD40 and let it dry. You can shoot some in and put the bike in different positions so the oil will flow to all areas. give it a couple of days to dry and your frame will be protected fairly well. A product designed for the job is Weigl frame saver. The outside rust is cosmetically ugly but inside rust can be fairly dangerous.