just want to say: unlike 1-2 and 3-4, there isn't really a in-between of bracket 2 and 3.
#Tasha, the Witch Queen deck needing cuts - Dimir
errant ginkgo
With the others it's more of a blurred line and is mostly up to how you personnaly operate the deck and card choices but with 3 there are set cards that bring you up and a change in how you are trying to win.