how much paint?

hey, about how much paint would it take to spray a whole board? not including water. in other words, if I wanted to spray a whole board 1 color, what amount of paint should I buy? I am looking at liquitex medium viscosity paint which would be thinned. thanks!

…about 2 oz.s a side for lighter/brighter colors,and about 4oz.s for darker colors.Always buy a little extra,for those…you know.Herb