1957... Same year as my Dynatron TV34 (and me!).. I'm inclined to believe it's the same chassis in that case, even down to the front control knobs and the FM radio feature.. Visually, it looks the same, and the only difference that stands out is the control triplet panel.. On the Dynatron, those controls are arranged in a neat row of three 'edge' controls between the two main front control clusters.. On this chassis, they're the usual EKCO style side mounted (hidden) triad.
The Dynatron TV34 also used a U26 for the EHT rectifier, ex-works, and I'd surmise the EKCO did likewise.
Once you reach first light, I'd bet on the majority of faults being in the frame linearity, and possibly an issue with the Contrast control, moreover, a constant need to readjust the contrast setting as the set warms up, and potentially, no sound or picture at next switch on (unless you readjust the contrast control again, and do the same routine as the set warms up) I have yet to investigate mine.
If you find the picture doing a crazy sideways twitch on bright scenes, that's were the Metrosil will need attention.. My Dynatron still has its original rod type.. The LOP stage will also make a characteristic 'chip-chip-chip-chip' sound in time with the twitch.. Reducing the contrast can stop the twitch, but obviously, the picture will look flat as a pancake.
The picture quality is superlative, once the set is fully up and running - lovely....
Dynatron CRT heater volts also = 12.6V nominal.