Michfish30, Yes you can multiple meats at one time, just make sure Poultry is on the bottom.
Try to put the close to the same area of heat so you have a better idea of the temps.Butts and Brisket are (IMHO)an easy pair as they both go into a stall.However if 1 weights quite a bit less than the other,put the bigger one on first,calculate the cooking time(1.5hrs./lb.@220*F).
This way you will have them coming off at about the same time; not always, but most the time I mix meats.
Here is a recipe for a white sauce(suppost to be BOB GIBSON'S)-
1-cup- White Vinegar
1/2 cup-Apple juice
2 teaspoons-Black Pepper(ground)
1 teaspoon -Salt
1/2 teaspoon - Cayenne
Mix well and serve at room temp. Stay well for two weeks,if it last the day!
Oops, I got carried away again,had chicken on my mind(or the space in my head)-
Have fun and,