Found this which is quite interesting and answering a lot of my questions about layer height vs extrusion width with a given nozzle diameter.

https://groups.google.com/forum/#!to...as/2FG_gUxa_fE

Looks like MatterControl was asked to allow setting the extrusion width, but hasn't done so and leaves it matching the nozzle diameter. So you could cheat by lying about your nozzle diameter to get close to the same effect as being allowed to specify the extrusion width.

The bigger issue I still have though is why I'm getting single wall prints that are double my nozzle diameter. Wonder if I just didn't notice it actually did an inner and an outer wall.