Well... as you use 1oz of weed in the brownies, how much oil would you need to smoke to get the same high you would get if you smoked this oz of weed? This is the amount of oil you should use to make the oil brownies as potent as the weed brownies.

If you never smoked one entire oz of weed (most people never did it), make the calculations with less. For example, estimate how much oil you would need to smoke to get the same high of smoking 1/8 oz of weed. Then, multiply this amount of oil by 8, and thats the amount of oil that is equivalent to 1oz of weed.