Hi Edredrop,
I found the large aluminum hooks on Etsy.com, $27 each. They were made by Halderman Designs back in 2019. I had them powdercoated yellow to stand-out in the bays. The hooks work great at keeping the hoses back against the bay walls. It took some education, but I would say about 60% of our customers use them. When we originally installed the Diskin booms, they would retract back against the bay walls. But when we added the 3' SS boom extension, the boom was so heavy, it no longer retracted on its own.
Ps. I just did a search on Etsy and couldn't find Halderman Designs! ☹