Awesome, thanks a lot for the voltage settings!
I could pull another 1000W PSU from one of my CPU rigs if needed.
I'm most concerned with efficiency though; do you guys know which is the best combination between hashrate and power draw with these units?
Well, if you've already purchased the Power Supply, then it's not important regarding the efficiency. If you've multiple choices, then a Platinum (or even Titanium) rated power supply is better. So is 230v vs. 120v if you're in a country that has 230v. As for the rating of the power supply, most power supplies will be most efficient at about 50% of rated peak power, so a 1300w power supply would be peak efficiency around 650w.