No, you need only like 5 grams of vaped (good) nugs, if mids about 7-8grams. (im european no idea in lbs sorry).
you heat up fatty oil or a stick of butter in pan, (not too hot) only left to simmer a bit. Then add the vaped (brown stuff) i wouldnt use it if you vape till black, to the pan and stir constantly for 30 mins. keep VERY low temp make sure it smells good not burned if your kitchen smells nice then your about done. Pour your weird looking brown oil into a big bowl with (important) A coffee filter with holes, or a filter of some sort to filter out the weed crumbles. You cover the bowl with foil, put the bowl of weed oil into your fridge overnight. (this is the main part, you cannot just pour your oil into a brownie mix , will barely give you a nice high) next day, you look at the bowl, and you will notice the top layer is a green butter sort, (this is what you want) and the bottom half(about) is water. What happend overnight is that the water separated from the laced oil. Now you take a knife and separate it and wholla! you have cannabutter. YOu want to use it in a brownie mix? lets say your mix requires 125ml of oil. you have cannabutter to when you heat up (slowly low temp!) in a pan will result in X amount of ml and just add the oil.