Was curious as to how much of a grain bill to use for an imperial style? The plan was about 14lbs pale malt, 2 lbs flaked oat, 1lb flaked wheat and 12 ounce Vienna. Was thinking of also adding 12 oz dextrose to help bump that sugar up a bit at 60 mins of mashing. Also this is for a starting boil of 7 gallons and hoping to target a 5gal batch post ferment. Any advice? Thanks in advance:)