Stepside under-bed fuel tank filler ideas please!

[68 Stepside]

Hey all,

I really need to dig up my old pics and start a build thread. There's a bunch of junk in my in-cab tank, so I said forget it, and bought and under-bed poly tank setup from Wes. I need ideas on fuel filler arrangement. My bed wood (sheet of plywood )is shot, so I've been contemplating a sheet of mild steel or diamond plate. Regardless of the type of floor I use, what have you guys done for a fuel filler? I've been thinking about a boat type filler, but would love to see some ideas.

Thanks for anything.