Hi again Flyback,
Well, if you have 17 resistors 11 ohms each that is 187 ohms. The power is P=342^2/187=625.5 watts.
Now you short out one resistor, we are left with 16 resistors of 11 ohms each, so that's 176 ohms. The power now is 664.6 watts.
short out another, and we are left with 15 resistors so that's 165 ohms. The power is now 708.9 watts.
So that's not going to work. So let's assume that you only switch off one of the two 22 ohm resistors in each parallel set.
Starting with 17 resistors of 22 ohms each at 342 volts, that's 312.7 watts (all relays are open).
Turning on one relay at a time the power increases from that 312.7 watts up to a max of 625.5 watts.
So the question is, is the range 313 watts to 626 watts adequate for testing your power supplies?
I had assumed that you wanted to test from 0 watts up to 650 watts, but if a range of nearly 300 to nearly 625 is good enough then you should be ok.
So what do you think?