Larry is 100% right. He has it figured out. Maintain your pit temp. Don't flip out, And let your pit cook for you. Oh yea, You get a temp spike or it goes a little low, But hang in there. Every thing you do has a effect. Note the effect and learn from it so you THINK next time and know exactly what to do and when to do it. Time and patience will prevail.Every pit is different. Every WSM is not the same.( as they get older, they get hotter) Till you spend some time with your little pit buddy. It Will tell you what to do and when to do it. You have to get to know it just as a friend or enemy. Keep calm and good luck. Thing with a brisket is they can fool you. Never had the same weight done at the same time. That's the fun of it for me on a large cater.