The reading list is growing. As mentioned in the previous post, there's the manuals for the oscilloscope, and today on the recommendation of the community in the Valves forum on DIYAudio, I've added these two:
Valve Amplifiers, Fourth Edition, Morgan Jones
Building Valve Amplifiers, Morgan Jones
Duly downloaded onto the Samsung tablet.
Meanwhile to keep the construction going, I'm currently building the dummy load I'll need when testing the amplifier.