Parker, can you post a pic of where the 2x4 cross member supports the sink? It's hard to explain, but I wonder just where and how the wood meets the fiberglass, and how the sink sits on the wood.
Shoot. At the rate I'm going, it might be another 5 years before I actually build this thing. The retired guy who gave me most of my darkroom equipment stipulated that he wanted one of the first images it produces. He might die before that happens. When we were kids there was so much time to kill. Now I have more money than time and it ain't no bargain.