We used a whole tube on our kitchen window. The bedroom window we thought would need just 1 tube but we needed more. The scrapers are great, they sharpen well but wear down quite quickly, not because they are inferior but just becasue they are plastic. They are the best ones we have used. We found that to do a whole caravan you’ll need maybe 2 to 4 scrapers and assume 1 tube of silicone for each window, 2 for really large ones.