I am in the process of buying a new stanchion also. Catalinadirect.com has them. Only problem is they are of a different design and the post through bolts all the way through the fiberglass toe rail. It is a stronger design, and the brace to the lower deck has screws in 1 1/4 inch on center. Old one is about 2 and a half. I have removed the stanchion, filled old holes with epoxy and may get a small stainless steel plate to camouflage old mounting brace holes. I think the gate stanchion is $140.
For other parts you can also check with Catalinayachts.com parts department. They don’t have an on-line catalog but you can tell them what you need. They like a picture. Contact Lisa who runs the parts department. Lisa@CatalinaYachts.com Unfortunately, my shore power plug shorted out over the winter and we had a small fire scorching the