0.8 fatwall for extrusion width calibrations

I found lots of 0.4 mm thin wall squares, but you can't print a single perimeter wall with a 0.4mm nozzle.
So I made my own 0.8 mm fat wall. I use it for Extrusion width calibrations using Simplify3d set to 1 outline perimeter, which results in 2 lines making up the wall width.

I also calibrate retraction and ooze control settings using two of these about an inch apart.