I use.....ummm trash compactor bags. They are heavy duty plastic...like almost 4 mil...(just guessing) thick...strong....light and cheap. If you are going to use them horizontally, just cut off the long vertical top part.....They are huge as far as their perimeter,,,girth? circumf...whatever.....peel and stick velcro with a couple of staples covered with tape as a roll top fastener should last you months. I got three weeks of hard touring out of them. I would never think of using cloth bags...I wouldn't trust them.