I have a Märzen recipe that calls for 7.5 lbs of light Munich malt. I've decided to break it up into half Munich malt and half Pilsner malt. The question I have is now I need 3.75 lbs of munich and 3.75 lbs of pilsner, but I can only by them 3.3 lbs at a time. Do I need to buy two extra cans of both and measure out an additional .45 lbs, or is this something that brewing software could help be compensate for by scaling down the recipe?