Well buddies, new progress to report....
First thing was flip and re-wire the rectifier socket PROPERLY.
Then I replaced the two wasted filter caps with these F&T caps. Same values, just bigger.
Pilot light works....but it worked before the filter cap explosions, too....but this is a good sign.
I'm not messing with that stupid copper cap anymore. I got a real rectifier tube for this thing....and it's alive. GZ34 tube.
At this point I'm already farther than I was before. I'm getting proper, expected voltages at the four filter cap nodes now. Even with the incoming voltage down low from the variac, things are acting as expected, so that's good. And with it wound up to full power and only the rectifier tube in place, I'm getting good voltages everywhere I should be, so far. So in go the preamp tubes. The first three did not light up at first, but a little jiggle on the fourth tube got them going. I think I have a shoddy solder on V4's heater wiring so I'll need to address that. But they are on for now. That's an easy fix.
So the rectifier is rectifying, the preamp tubes are lit up like it's Christmas, and the plates, cathodes, and grids are getting expected voltage readings. A double check on the bias, so what the hell.... in go the power tubes. And the most beautiful sight ever, they're all glowing nicely.
Nothing has exploded, no tubes are red plating, the bias is good, so with nothing plugged in I turn the volumes up. I get a very very slight faint hiss from the speaker just sitting face down on the table. I'm not sure if that's awesome or terrible. I'm hoping the amp is so quiet that it's awesome. So I grab a guitar, and.....
IT'S ALIVE!!!!!!!!!!!!!!!!!!!!!!!!! 
The amp makes sound! Guitar sounds! Fender amp guitar sounds!
I tried the normal channel and vibrato channel. Both work. And at this point it is shockingly quiet....as in no noise. There's no weird hums, pops, or hissing. Just getting sound from the speaker is a massive win. Never mind if it's good or bad sound at this point. Any sound is good.
So we made a huge step today. Next will be to test the reverb and tremolo. I hope they work.
