I would invest in a powerful PSU for CFXing those GPUs, something like Corsair HX850 or Seasonic X-850.
850W is an overkill for his setup, man. He will be absolutely fine with just HX 750
, even in a long run, for a long time.
This has the double plugs I need?
The GPUs you decided to buy need two 6-pins each, that's four 6-pins. HX 750
has four 6+2 pin cables. Exactly the number you need, nothing less or more than what you just need.