The maximum draw on a non-OC'd 760 is 170W
(14.2A on the +12V rail not 30
). 6.25A will be supplied by the x16 slot, so the 6-pin PCI-E's need to possibly supply less than 8A (96W) between the two (a 6-pin can deliver up to 75W (6.25A) apiece).
Overclocking can add significant power increases (and that card is 11% factory OC'd). Literally a 25% OC ballpark a 25% power demand increase. Even though that card has a 6-pin and a 8-pin PCI-E connector you could not possibly OC the card on air (or even liquid) and need that much power as nVidia's spec sheet shows, two 6-pins supplies 150W / 12.5A of power. So don't sweat it---well unless you can get a 50% OC in which case show us the GPU-z screenshot!
Maximal power demands only occur when running an app designed to test the GPU or in intense gaming. Most of the time the PSU never breaks a sweat.
That XFX is an very good quality PSU and a great price. But the Rosewill is a crap PSU quality wise (made by Solytech). If you assume it actually is capable of putting out its power specs at 50C, or even 40C, then the first +12V "rail" which supplies the mains at 15A which will include the x16 slot's 6.25A contribution. The 16A on the second "rail" should easily handle the remainder demanded by the video card.