I spent part of the last two weekends working on the Kay Vanguard. I built a bridge, installed a new 1/4" jack, and experimented with shimming the neck.
My original "new" idea for a replacement bridge was to make one of out bone. I bought some bone blanks that I could cut and combine into something that would be the same size and shape as the original wooden bridge. It took some time because I had to let the glue dry and try to grind the parts down accurately. When it was almost done I became convinced it probably wouldn't be strong enough and so I didn't bother to notch it for the strings. It looks good, though, and maybe I'll find a use for it someday.
I made the metal bridge by welding a nail to a piece of solid square steel (I think it actually might have been from a toilet paper holder). I drilled holes to match the post locations and ground it down until it was about the the right height with a radius to match the original bridge. I made the string slots with a file from a set of jewelry-making tools.
With the new bridge installed I could finally string everything up and evaluate the neck. Things seemed pretty good until you get up to the around the 12th fret. Above that all the strings were bottoming out on the highest fret. That was the bad news. The good news was that replacing the input jack fixed the major noise issues. There is a hum that I think will go away if I attach a grounding wire from the electronics to the tailpiece.
The other good news is that I think the pickup sounds pretty cool. I only played it softly (it was early in the morning) but I'm pretty happy with what I've heard so far.
I loosened the strings and detached the neck. It had been shimmed with some cardboard. I tried adjusting the neck angle by making the shim thicker farther away from the body, and that seemed to work: I could now play all the way to the 17th-18th frets with no major issues. At this point I noticed that the 19th fret (the highest fret) was pushed up out of its slot a bit. That probably accounts for a good portion of the problem. If I had better skills and tools, I'd consider refretting the entire neck. I don't have better skills and tools, though, so I'm going to wait for another day to do that. For now I'm just going to file that 19th fret down so it doesn't get in the way.
Satisfied that I'm on my way to a playable guitar, I took everything apart to prepare to refinish the body. I've got a vision for what I want it to look like. I'm not sure I'll be able to pull it off, but even if I can't I like the way this thing sounds and I'm learning a lot by going through the rehab steps.