Question about accessories: I have two Downtubes, a Mini and an 8H, and I can't find a decent waterbottle system to use with them. Because the downtube to which the cage attaches is close to horizontal, the bottle has to be a snug fit or it flies out. The only bottles I've found that fit are the ubiquitous soft plastic waterbottles with the pull-up spigot. Unfortunately, those bottles when horizontal tend to leak out the seam where the cap screws on to the bottle. Has anyone else had this problem and come up with a decent solution?