Will be doing this brew at the end of the month. I forgot to ask, do you alter your water. The water here in Bend is very soft. Ca is 7, pH is 7.8.
Probably the only thing you really need to worry about, with the amount of dark roasted malts, is that the pH of your mash doesn't drop too low. Very soft water would allow that to happen more easily. Just mash-in, measure the pH, and adjust if necessary (Chalk or, preferably Pickling Lime to raise the pH).