I happen to work at a company that makes paper towels… For years, we had paper towel rolls in our rest rooms (now we have the fancy no touch towel dispensers…). In the old days, a very effective towel rack consisted of a hole on one end and a U on the other end. Both of these could be made with a piece of plywood. They used a 1″ dowel for the rod. These worked quite well. That’s what I plan to do.