I might be an over-killer, but when I make brownies or cookies (and I do so weekly, SR is the bomb baby!), I measure out the number of grams of magic per number of finished items. So if I know that my usual cookie recipe nets me 24 cookies (actually it'd be more like 28 but I "have" to test the taste while I cook) then I make the oil or butter for that recipe using 1g/edible as my final goal. So if my brownie recipe calls for 1/4 cup of oil and it makes 18 brownies, I infuse the 1/4c oil with 18g of the good stuff, then each brownie contains a 1g equivalent. That's a fairly large doobie for reference.
That way it's easy to know how much "magic" each cookie/brownie has and how much that's worth knowing the cost of ALL ingredients. Please feel free to PM me with any questions I might be able to answer for you.