For the 2016 AC/DC concert a catwalk and B-stage extend into floor sections 2 and 3. According to the most recent seating charts - within these sections - seat 1 is located closest to the center of the floor and to the long stage.
In all other floor sections seat 1 is always located on the right aisle as you face the stage.
Sections 1A-3A are among the cheapest way to get floor seats at the Tacoma Dome. Although these sections are pushed back from the stage, they provide a comfortable head-on view to the stage. These sections won't have the same energy as traditional floor seating, but they're also a fraction of the price.