Man that is an awesome recipe and a helluva bucket list item. I don't know if I've ever seen a 150# snapper. The one I found was laying eggs and wasn't big enough so I let her go. I am now on the lookout for the big one.
Yeah, Escoffie recipes are way over the top. He was a chef for European aristocrats back when folks ate turtles are carp as fine dining. Obviously, you would need to adjust the recipe for size.... 50 qt Stock pot? That won't fit under my stove hood