Position the lower "hook" so that it takes a slight amount of pressure when you attach the top clips; you should have to very slightly push down on the top clips to get them to close on the rack. My Rollers and Packer Sports Pluses, and the earlier Packer Pluses, didn't rattle when they are installed this way.
I do like the idea of the earlier bungee connection to the bottom, though I have never used it. Combining that with the proprietary Ortlieb clips would seem to be the best of both worlds. But you *can* mount Ortliebs with no rattles.
Question: the new Rollers have clips that don' grab the inserts as closely as do the Packer Pluses -- what gives? The inserts on the PP's never fell out; those on the Rollers occasionally do. I suppose I can glue them in, but why don't the Rollers' clips hold them tightly? FWIW, the inserts now used on the Rollers were removed from the Packers.