I want to brew a Porter and add some Peanut Butter Extract when I keg. I have some Watkins Peanut Butter Extract in 2oz bottles. It only going to be a 3 gallon batch. Should I use only 2oz or add the other 2oz of extract for a total of 4oz. I could make a 5 gallon batch out of it and just use both, I dont know, what do yall think? Thanks!