I did some further testing this weekend. I was able to borrow a thermal camera adapter for my phone, and using this I could inspect the boards while they were running in the cabinet. Photos aren't the highest quality, and the angles are weird due to the space limitations of shoving my hand and phone inside a live cabinet.
I didn't find anything outrageously hot, but I did get some results. Keep in mind, these images show the hottest thing in the camera's view, and the coldest. Usually that range is from 22°c to 28ish.
In the power section, I can see some resistors and diodes get warm, but nothing unreasonable (see pic).
There's 3 resistors near the back (R137, R138, R196) that get up to 48°c, but I think that's normal for giant resistors like this (see pic).
On the neck board I can see the main IC201 gets warm, as do the large heat sinks, but nothing hotter than 31°, so it seams fine.
The signal input board has a couple of diodes in the corner that get pretty hot (45°) but I recall the dude in one of those youtube video's I posted saw the same thing happening to his board. I guess it's normal. I tested the diodes and they still work, so I guess it's fine? (see pic)
The one thing that really caught my attention was this somewhat hot spot over by R469 (the big ceramic resistor). R490 and IC404 were in the middle of that. I have a different pic where that IC is up to 55°, which is suspicious to me (to be continued).
And I was curious what the tubes neck looked like so I snapped a pic of that for fun.