I have a similar build:
I had to use to use two power supplies (AX1200i and an HX1000). Doing a kill-a-watt test at the wall, I was pulling in over 1700w so using the two power supplies was the best option. I used a psu2psu adapter - really easy to use and, so far, very reliable.
If you can, I'd go up to 480 radiators (if you could get three to fit)....