It was probably one of the best I've done. 18lbs - found last week on sale for $2.99/lb. Put it on about midnight last night, pulled it little after 3 today. Someone on here had mentioned a coffee rub before and I've been meaning to try it. Someone just asked the RecTec guys if they could share the 'Espresso Joe' rub since they don't make it anymore, and they did!
You'll probably want to do the math on that and downsize it a bit. This is probably my new favorite brisket rub though.