My wedding cake coming up for the 14th is driving me INSANE!!

My pans are all 2" pans So I figured if I filled them full they would bake up over the pan, then I could tort them (2x) and fill (with fillings) to give me close to a 3 1/2-4" tier, correct? So I should order the 4" dummy...tiers are 8", 12" (dummy), and 16" rounds. The cakes are going to be frosted in all buttercream so I could lay on the frosting thick...hahahaha

Ugh...I thought the stupid pans were 3"...nope they are 2".... I just want to make sure that I do not have a noticably smaller (or larger) tier in the middle...lol

Thanks for the help.