Personally, if i was you, id put a 10" in front of the condensor, and a 12" in place of the std fan (to the left), on a hot day, it will get slightly warm. 2x10's might be insufficient. - If you want pics of my setup, let me know and i'll email them to you.
Also, when you do put the fans on, go to your hardware and get some of that adhesive foam stuff they use to seal doors etc, (its about 10mm wide and around 6-8mm thick, with adhesive on one side) and when you take the radiator out, put this around all 4 sides of the core, about one inch in from the sides, and also run one length down the middle - so you are basically putting a window frame around the radiator core, so that when you put the radiator back in, the foam mates up with the condensor, therefore all air flow from the fans is forced through the radiator, and not around it.
Also dont forget to reverse the blade and polarity of the inner fan, as it will be sucking air instead of blowing air...