Im not at home right so I cant take a picture of it, but the dm10x rack has three posts that have an opening at the top for the alesis downtube to fit. The fastener for these posts will only close around a 1" diameter downtube, anything less means the default wing screw isn't long enough to compress the plastic ring, it won't secure a 7/8" downtube at all. Replacing the wing screw with a longer one causes the plastic ring to compress into an oval, which means it won't hold evenly (even at full tightness you can pull out a 7/8" downtube).
It's a really stupid design on Alesis's part to make fasteners that only work with 1" downtubes considering they don't even sell their downtubes seperately.