My PSU box has the maximum current for the "12v1" at 17a and the "12v2" at 18a. I was reading that I should have something like 24a on the 12v rail? Will my psu not work or do I combine the values for 12v1 and 12v2?
Uh, no. Unfortunately it's not as simple as adding the two +12V rails. Take a look at the sticker on the PSU and see if it gives the watts supplied to the +12Vs. Take that number (watts) and divide it by 12 to get the amps supplied on the rails by your PSU. In either case I doubt it will be enough. Most call for around 28 amps. Head over to the PSU section and look at the PSU reference lists created by mpilchfamily (and PSU 101 + 102 if you want to learn more). Any PSU on that list is made by a reliable company or is a reliable model.