On pages 17 and 18 of the Version 2.0 Pompei Oven Instructions, there are some CAD drawings for the hearth and oven in a corner installation. The largest shown is for a 49" outside diameter oven. To my way of thinking, if you have
4.5" bricks on the opposite sides of the circle totaling 9", this drawing will yield an oven with a 40" diameter cooking surface. I assume that when FB refers to a 42" oven in their plans, they are talking about the cooking surface, which would require a 51" outside diameter and similarly increased hearth size. Is my thinking correct?

If so, does anyone have a CAD drawing of a corner hearth and oven in this configuration that they would like to share?