Power Transformer/Power Supply "Rules of Thumb"?

[loudthud]

Heathkit used to sell a power supply that was varable with an output of 400V at 100mA. A pair of 6L6s regulate the HV. Current and Voltage meters on the front. Also included are a bias supply and heater windings. Fairly common to find them on Ebay. They work well after replacing all the electrolytics.

I have a Navy surplus supply that is variable 525V at 500mA. Weights a ton because it uses choke input filtering with oil filled caps. The voltage adjust knob turns a pot and a small variac. Six 6L6s are used to regulate the output.