Steve - Do your tanks have baffles?
The tanks certainly ought to have 2 baffles each, based on their fore/aft length (6ft). The boroscope will quickly tell you. Maybe you could tell by tapping the side of the tank, but yours, like mine, has soundproofing on it. As I mentioned on the site, I have so far failed to identify anyone who has done the tank replacement, although I am aware of a couple of boats that have had it done by previous owners.
The presence of baffles will obviously make cleanout more difficult unless you put in 3 accesses (= total 6!). I have a friend with a GB36 who cleaned his tanks through a single access - I think he pushed a rod or a tube through the gaps around the baffles. Horrible job.
Thinking more about the ideal plumbing setup - I would like to air a thought for the pickup which could be incorporated IF I do indeed put new tanks in.
Briefly, I would put a largish connection (1"FNPT?) on the wall of the tank right at the lowest point. On this connection I would install a 1" ball valve and then immediately a 1" strainer (very coarse filter - only catch anything bigger than 1/8 - 3/16", say. After that I would run fuel hose - 5/16"or 3/8"ID - to the primary filters, then similar hose to the engine. I would include the electric pump for priming/get-me-home similar to what I have now.
The strainers that I see available are called "Y-strainers".
I think the philosophy should be self evident - you must avoid blockages INSIDE the fuel tanks - for this you need a large-bore exit leading to an accessible screen of some sort that can hold some junk and only let through solids that would still easily reach the primary filters to be trapped there. Either that or you need, say, a 1" hose from the tank to the primary filter - apart from being very bulky, the filters do not have a 1" inlet, so this is not an option.
Example of a Y-strainer:
https://www.amazon.com/Zurn-1-SXL-L...d=1&keywords=y+strainer&qid=1607969340&sr=8-9
All comments welcome!
Nick