I know it has the needed 450W but I'm unsure how the amps work. The video card says it needs a minimum 12V current rating of 24A. The PSU has 3 12V rails at 18A each. The PSU guide for popular video cards recommends 36. So since I'll be using 2 of the 12V/18A rails does that work out to the 36A needed?
The minimum requirement of 12V 24Amps is for the WHOLE system...not just the video card.
And that Corsair HX520 has plenty of power for your whole system. In total it has 40Amps of +12V. (max combined +12V = 480 watts divided by 12 volts gives you 48 errr .. 40Amps).
Your GTX 460 has a peak demand of around 181watts (15Amps) with a typical full load of around 137watts (11.4Amps). Palit GeForce GTX 460 Sonic Platinum