Man... 28g of weed is TOO MUCH!!!!!
Dividing it for 20 brownies, it means 1.4g of weed per brownie.
If done properly, one brownie with 0.5g of weed is more than enough for a very high HIGH...
I would suggest you to use far less weed... like 1/2 of 1/3 of ounce. And even so the brownies can be VERY potent... eat ONE, and wait some 2-3 hours until the effects start. Remember that eaten weed takes far longer to kick in. If after 2 hours you dont feel anything, then each another. And wait more some hours. Doing so will avoid the danger of eat too much at once and get TOO stoned.

Look at this thread:

http://boards.cannabis.com/recipes/1...ial-guide.html

There you will find the best way to use the weed in any recipe. Use the "weeded" oil you make using this recipe instead the vegetal oil, when were make the brownies.
And good luck! :thumbsup: