I am relatively new to smoking and plan to cook 4 butts in my electric smoker this weekend. Until now I have only smoked up to 2 at a time. My smoker will hold 2 butts on a rack, so if I do 4 I will have one rack underneath the other. My question is there any thing I need to do differently given the upper butts will be dripping on the lower ones? I plan to use a dry rub. Thanks.