I would have updated the insolated variable AC supply, with a DC output with a 0-390V DC, inspired by a video from Tony Albus. The maximum output voltage surprised me a bit 280V AC * √2 = 394.5V DC.
I would not make the DC output without a voltage meter. There was no room in the first solution, therefor i have build the DC output into a separate enclosure.
The discharge resistance is important, it prevents you from getting a strong electric shock from the charged electrolyte capacitor. and must be able to handle some watts. Starting power across the resistor is 68W and the total energy discharged to zero volts is 17.2 Joule.
Therefor i build the DC supply into a seperat chase, origilal to be suplied from the insolated variable AC supply, but insted i ended up modifieng the isolated variable AC supply, with current limiter.