I saw your post about a cat you are looking to build. I thought I'd reach out privately to tell you I have a boat like that in brokerage right now. It's a knock off of a gunboat 55. Called a DH 550. Now it does not have the full open layout between the hulls but it was built to be sailed from the inside and the steering helm is there also. So the guests can sit inside or out and enjoy it. Anyway, have a look at the listing. If that interests you, let me know. Also the cat you are talking about building will be in excess of $500-700K if you start from new.
You can find the listing in yachtworld.com and search for DH550. This forum will not allow me to input the hyperlink in this message.