Thanks all for the feed back.
Can I ask why you wouldn't just glass in a fiberglass tube as a supply and pickup?
I spent allot of time debating this very thing. The area that the fill connects to tapers to about a 4" section. I am building sections of the tank then tabbing them into the bilge
and laying up all together inside the bilge, because of the complex angles in the tapered area I was not 100% confident that I would not get any pin holes in the hard to access areas. In the end the SS thru hole was less time consuming I will build a support saddle adjacent to the barbed fitting to attach to the fill hose. I plan to pressure test the tank on completion, will post some pic when complete.