Yup it was the doubler. One of the doubler cans was wide open I did not have a 160uF 250v on hand so I subbed a 250uf 250V in for the time being and it corrected the horizontal shrinkage.
I kind of suspected it since I had a NEW doubler cap in my Silvertone fail and the symptoms were the same. After replacing the doubler I brought it up on a variac with my typical over caution, and as I approached line voltage I started to hear BAD corona sounds from the HV cage. My over caution proved merited; there was perhaps the worst corona I've yet seen in any set coming off the HV line. It had to be over an inch long, that purple spark, and if I cranked the variac closer to line voltage it turned to an intermittent arc that caused the CRT neck to light in step.
My camera did not want to capture it, but if you can see the black spot in the red wire with a tiny purple dot in the middle where the red wire is in-front of the HV rect. plate cap that's is where the arcing was.
Since the wire had arced through I decided it was best to just replace the wire and HV connector suction cup with one salvaged from an abandoned SS set I scrapped. I also cleaned the rectifier cup, and removed the odd blob of clear silicon that someone put on the interior of the cup for reasons beyond my comprehension.
The cup did get better with a bath in the sink, but there was waxy dirt on the interior that soap and water refused to touch. To deal with that I broke out the big guns and used 'goof off' to remove it. That stuff can dissolve PVA and make the surface of those clear plastic covers on turntables turn rough and hazy. Since the HV cup is not clear and almost never seen I decided who cares if it messes with the finish if it gets the dirt off. Some pictures of this below.
I noticed while doing this that the focus rectifier tube socket was connected to nothing and that a 60's HV diode was installed. Not exactly correct but it is period and does seem to work decently so I think I'll leave it be for now.
Now I had a few problems remaining the set had not been given a proper gray scale, purity, or convergence setup in way too long. Also the vertical don't want to fill the bottom of the screen, and for some reason it seems the chassis hole marked 'vert. centering' looks to never been populated with a control...Ugh! That and I wanted to set it up before turning the color on.
It just don't want to be pure though, and the static convergence magnets don't have as much range as I'd like to see....I think I'll try a couple of spare purity rings I have stashed away next time I try to redo the set up. the results are below.
After giving up on that I tried the color, but that was barely functioning. Most of the color stage tubes were weak or shorted so I swapped them and got almost perfect color bars....Only which one is supposed to be the blue-green bar and which is the green bar?
There are also dirty tube sockets in the IF that I need to deal with, and for some reason it seems to tune channel three better with the tuner set to two.
I got this far without a schematic or any service data beyond the tube layout inside the cabinet, and I'm proud of that. But there are only a few tricks I've got left before I need to grab a reference to see exactly where it is off speck.