Trying to build universal connector for 8YP4 Picture tube

[Zenith26kc20]

I use jumpers to connect mine. Look at the pin out and compare them.
I know, a PITA!

[Electronic M]

I've got all 3 monochrome test tubes 5AXP4, 8XP4, and 8YP4. My yp came with an adapter for the predicta style bases (the default YP base was used on some early 60s 19" Zeniths and some late gen early 60s Sylvania Halo-lites)

My XP has a couple home made adapters and a pre-made one... If you buy enough tube caddies, and boxes of brighteners you wake up one day realizing that you already have half the adapters, and realize that you have enough duplicate brighteners to make the rest...
Based on what I've seen and the main monochrome adapter on my B&K 466 CRT tester most monochrome bases are wired one way... Except for the predicta style bases that are wired 2 ways.

If I was scratch building one from my brightener socket and base stash I'd probably wire a male octal tube base to the female 8YP4 CRT socket, and wire each male CRT base/base wiring variation to its own female octal socket for minimum use of parts brighteners, fast interchange and provisions to use an octal extension harness (many color test jigs came with two or three 4' octal extension cables and my color jigs are no exception).
On the octal I'd cluster the 5 essential CRT leads (H1, H2, K, G1, G2) with H1 and H2 straddling the locator key as was standard practice on CRT bases, and I would put the focus on the center pin of the remaining 3 to minimize chance of arcing... Provision to open the focus lead and or connect it to G1 or G2 isn't a bad idea.