So since I'm trying to shoot close to 30 IBUs should I then only be using .3 oz of Chinook instead of the .6 oz to get me 10.55 IBUs which is 1/3 of 30, and then at 20 min add 1 oz. of Cascade which gives me another 11.47 IBU's, and at 5 min add 2 oz of cascade to get me another 7.55 IBUs with a...