id say the gold would do you bud unless you want to spend the extra for the swanky monitoring software. also the guv said it would be fine and i would trust virtually everything the man says when it comes to tech but there are counless psu calculators on the web that could give you a bit more peace of mind
also im presuming each of those cards requires 2 pci power cable it may come down to you needing 2 smaller psus just so you have enough power points like in toms overkill3d vids i believe he uses 2 psus with different coloured cable to identify between which psu the power is coming from if you understand what i mean just because there are that many power cables needed so yea that also may be a thing like 2 ax850s