PSU looks fine.
Since it has screw in terminals, you don't need a terminal block.
Here's what you need:
Crimp on fork or ring shaped terminals (.17" should be fine),
18 AWG wire, preferably in three colours: red, yellow, black
56 pin jamma edge connector
One 6 pin VHR-6N connector + 6 pcs SVH-41T-P1.1 contacts
Heat shrink tube
Soldering iron
Crimping tool. Pliers will also suffice
Red wire is for +5V, yellow for +12V and black is for ground
Jamma pinout is here:
https://wiki.arcadeotaku.com/w/JAMMA#Jamma_connector_pinout
System 2X6 power connector pinout is here:
https://wiki.arcadeotaku.com/w/Namco_system_256#Connectors
Here's how I would do it:
Cut one black and one red wire to same length (at least 1' long). Solder one black wire to all four ground connector pins and one red wire to all four 5V connector pins on the jamma connector (this isn't usually recommended, but power draw on the IO is very minimal. One wire each will be fine). Put shrink tubing over the exposed contacts. Crimp your fork or ring terminals to the other ends.
Cut two red, one yellow and three black wires to same length (again, at least 1' long). Crimp your six JST contacts on each end. Put them into the plastic housing in the correct order. Crimp one fork or ring terminal to both red wires (twist tie them together), one terminal to yellow and two terminals to black (one terminal has one black wire, the other two).
Altogether you should now have two red, one yellow and three black wires with terminals on them to put under the screw in terminals on the PSU.