I am in process of figuring out dinghy chicks to mount AB 310 AL on my boat deck. I reached out to two places to fabricate based on AB CAD drawing. One uses 1" thick HDPE (Starboard), the other welded aluminum. Both were in the $1500 range, plus shipping. Attached pic is similar style but not exact for my AB
McMaster Carr sells fiberglass sheets of up to 1" thick. Cheaper and stronger than HDPE but more difficult to work with. I can purchase 3-inch SS angle cut in 3-inch lengths from Online Metals.com for the base attachment points. Roughly $400 in materials and a weekend of futzing with power tools.