I’m surprised that you had difficulty running it without a print head. I know there is a pencil holder tool that has no electronics in it. Maybe because the GCode was generated in CNC mode instead of 3D printing mode?
I know there have been several different projects to reverse engineer the communication to the print head. It would be cool if you had some electronics in your print head, and it used the “feed filament” signals to dispense paste.
I was hoping more of this documentation would have been published by now. The original promise of open source hasn’t really happened yet, and I feel like v1.0 owners are going to get left behind if v2.0 ever publishes their information.