Math for determining needed brake size

[johnparts]

Hey guys, I'm wondering if there is an actual math calculation for determining brake size on a car as needed or recommended by weight power etc... I have a goal weight of 3200 lbs with a hp rating in the 750 range with lightweight 20" wheels front and rear. I know most guys would say run the biggest brakes you can run inside your wheel because of the 20's however, my budget dictates more of my build then just throwing parts at it. I was looking into running a 13" vs 14" front brake system because of the nearly $1000 difference between the 2 and a 12" rear set up vs a 13" rear because again the budget calls for it. Is there a way to determine if this will be enough brake for daily/occasional track duty.