Jon,
BTW - sorry to get off topic. Ham radio is fun though.
Not a problem. You tube/radio guys are all the same!!LOL!! Fortunately for me, my Brother-in-law (kj4ama) is the same way. He's actually the real ham guy in the family. I just listen to you guys on an old DX-160 with a half wave, horizontal dipole connected to it. Haven't taken the time to get the license yet. I do play around with an 11 meter set he gave me, from time to time. But....He's the one who loaned me the tube tester.
As an alternative to the can cap, the various cap boards are excellent, these mount under the OPT, and use the same mounting screw hole pattern. I've seen these from Triode (SDS Cap Boards) and Cyrus Chong (cchong on e-bay),
Are you saying the various cap boards that are available are interchangeble with various input boards? This is something I had wondered about, but was almost embarrassed to ask.