You could also use contact cement and velcro. Cut strips of the "fuzzy" velcro and use contact cement (pliobond, laminate adhesive, hot melt) on the bellows, then use a small patch of the hooked velcro glued to the top of the front standard for your fastening point.

For bellows sag on the 8x10 with a long lens, I have used a couple of hunks of foam blocking to place between the camera bed and the bottom of the bellows. Depends on the extension and the shot. tim