1-1/4 cup (or 8 oz.) in ~ 2 cups of water, boiled for 15 mins., then cooled is standard. DME is all I ever use.
That said, I did do a wheat about a year ago whereby I used 1-3/4 cups b/c I wanted a highly carbonated ale. I got it! No exploders, but I think I'll stick to no more than 1-1/2 cups from here on out!