Well I would use the milligram math. Expect to yield 15% of your weed weight as milligrams of THC . So an ounce would be 3500 milligrams. Which is like 7 extra potent 500 mg edibles. So it depends what you want to make with the butter and how high you want to be. Because weak legal edibles are only 10 mg. The most I can get to absorb into a pound of butter is like 3 or 4 ounces of bud worth. Before it's not buttery enough anymore. A standard Grey market edible is 50 mg.
I dont really make brownies etc I usually just like to put a small amount in my coffee or on top of my food so I like it strong... I usually use trimmed sugar leaf at about 35g to 40g per 250g of butter... Im thinking of using about 20 or 25g of flower when I make this batch judging from what people have said to me