This is what I got at the business end.
12v rails are 23.5Amps = 282 watts
5v rails are 0.6Amps = 3 watts
-2 sockets on the bottom are for 12v to the motherboard, but I'm not sure which is ground or power
-6 pins in front are related to 5v, first pin on left is ground and last pin on right is 5v, not sure what the 4 in between are.
You should just use ur multimeter to verify this, Keep your black probe grounded and check the voltage with the other probe. I also seem to have read about the 12V line needing a load before a relay closes the circuit. Go ahead and test it out and let us know