Depending on the brand a gallon of base should be plenty. Dupont, matrix, and genstar mix 1:1. cheaper bases like nason mix 2:1. If you buy high solids clear (mixes 2:1:10%reducer) you'll have over a gallon and a half sprayable. Clears that mix 4:1 will give you one gallon and a quart sprayable. Either way you should have plenty of material.