Just a thought... But is there anyone you know or a good local marina that can take 1/2 a day and get the tank out for you to document specs? I think that would be the safest way to go. Wish I were closer I would gladly help.
We also know that the same tank (again we are assuming it has never been replaced) fits the 222 Express Fisherman so you again could try Phil at Alloy on this model. Still, in rereading CJs tank replacement thread, his is an 85 gal. tank. That is the standard model for CCPs that came with that size. Phil made that tank so I'm thinking you can only get closer by actually pulling the existing one you have. I'd bet the farm it would be the same size.PS....FMT did return my call but refuses to release the cut sheet unless an order is made and paid for, which is understandable. They did state that the cost would be $823 before tax and shipping.Good luck.
I can't find CJ's tank replacement thread. Do you have a link?