My last thoughts to optimize the Tube-I-zator goes to the B+ High Voltage lines.
To get the maximum flexibility, i have made splitting points in the lines.
The splitting of the anode psu lines brings upgrades possibilities.

You could use e.g. a tube rectifier with C-R-C filter instead of the onboard andoe psu or
switch to a regulated shunt psu, witch in my mind brings the greater sound quality upgrade.

With the experiences from Salas low voltage shunt on my DAC project in mind,
i have made an upgrade module for the Tube-I-zator based on his HV shunt circuit design.