Nice project Opera House.
Simple and easy to make.
It does have several possibilities for modification and other uses as you mentioned, again probably easily implemented.
I ain't going to throw away another old computer PSU.
Those things are a treasure trove of usable parts n pieces...even the housing, fans..
Thanks for taking the time to type this--draw the schematic, take the pictures, etc.
But you might want to take another look at those power resistors in series/parallel combination and end wattage, but it could be just me and "math", I didn't pay much attention way back when I should have.