these numbers are rough, not accurate, but close.

The 8A 12V power supply is enough to run multiple units, 8A 12V offers a power output of around 96 Watts. When converted to 5V at the USB ports, that offers around 19 amps of power at the USB ports. If you remove 10% for loss (and thats ALOT more than real numbers) you still have 17.28 Amps of power.

At the default frequency of 100MHz, the NewPac runs at 22.8 GH pulling 3.5Watts or 0.7Amps, less if you add cooling. long story short, at default frequencies, you can run a full gekkoscience hub (6 units) without a problem.
When properly cooled, the power draw is actually less. when cooled to the point you can actually hold onto the unit, at 200Mhz, it pulls somewhere around 1 amp per unit. again, more than enough for 6 units.

just remember the Units should be in 2 -7. use ports 1 and D for accessories (fans).