I'm brewing an oatmeal stout and just found out that the oats I was planning on using need to be converted before adding to the mash by pre-boiling them. I'll use 1-3/4# of oats. Should the water I use for this be taken from the total amount of water calculated through Brui'n Water or should it be in addition to it? I know oats soaks up water and I don't want to end up shy on volume..