@3D-Print said:

> I am trying to find where I can change extrusion from absolute to relative in MC and MS (i.e. M82 and M83). Is this possible?

Extrusion is hard-coded into MatterControl as using absolute. You could change this if you were to edit the code and re-compile, but that's up to you.

> As well, can I set the MS to use firmware retraction as I would like to do with the Duet?

MatterSlice does not support firmware retraction. We're open to the idea of supporting it in the future, but would need a compelling reason to do so.