Here is a great thread pertaining to your problem http://www.overclock.net/t/1457426/radiator-size-estimator I actually learned a lot from this and hopefully it'll solve your problem. But to solve your issue, yes; additional Rad will help your cooling. Other factors you may have to consider is the flow rate. I'm not sure what pump you're using but the more added the more constricted.
8/7/15 at 7:50pm