Cliff,
Great link.
However, I think the power supply they show should be fused and some sort of regulation is needed, due to line voltage variations.
Also be aware that the filaments should ALWAYS be turned on and warmed up first, before any B+ is supplied.
Failure to do so results in DC filament tubes a condition known as a "Frozen Cathode".
This happens when the B+ is applied before the filament is warmed up, and the electrons are stripped off the filament/ cathode.
This is why high power transmitting tubes are always "warmed up" before applying the B+.
I had read about this decades back, and had it happen to me one time on an old battery radio.
Adding a time delay relay to the B+ supply is pretty simple and cheap, and can save the tubes, (like your 1L6) from being ruined.