Let me know how I can help test this. I can get one PSU for starters, but don't want to deal with soldering wires for the very reason you stated. Breakout board would be super cool to try.
The moment I can get a part number for a card edge connector that can support the wattage; Ill be drafting up a PCB which will be stupid simple. Probably make it like the typical breakout boards you see; maybe with a voltage readout, but probably bare and basic to keep costs down. Should be able to happen with a simple single sided design, or at the worst with a double sided board.
At first I planned on scavenging the second half from an old AT 16 bit slot; but its too much work to desolder, etc.... plus, i'm not sure how much wattage you would be able to cram through a connector from the 80's.
if you wanted to solder it properly, you would probably have to have a reflow table set near 200, and use a solder gun (like for automotive) to tin the contacts; but those boards have THICK ass traces and eat up the heat pretty quick. The other PSU I soldered to was even worse; and it was fingers instead of a card-edge. All the soldered cables, (including the PS_ON line) ended up just not adhering fully. Removing that connector on the not pictured PSU; I wasn't able to do because I lack the hot rework station and have no room at my home for one.
Hopefully I have time to revisit this in the next few months.
Working on rewriting my batches, daily life, taking care of my chameleon, trying to keep healthy/not bed ridden and keeping myself fed has been a chore in of itself... lol