You could alternate those bottom ones about half way thru.
Doesn't hurt to open the door then,and let out some moisture.
As you get closer to 3/4 done,you can tell what is finishing faster,and move them to cooler spots.
If you haven't checked it,the top rack could be hotter-as heat rises.
You could also cook more at 235º,at your average cook surface,if that helps your timing.
Put your probes in your smaller/faster cooking butts,so you'll know when to start pulling them.
If you get too far behind,later in the cook-250º won't hurt anything.
You don't "have" do do anything,but take good notes.
