Hi,
Not sure if this will help you. Im running a Duet 3 6HC with a raspberry pi3b+. My cnc is an Openbuilds Lead 1010 with high z mode.
I use the Ooznest post processor for fusion-360 as the Workbee lead screw cnc is practically the same. Ive loaded the post processor into my Fusion 360 Library> Assets> CAMPost.
Fusion-v1.0.1
https://ooznest.co.uk/wp-content/uploads/2019/02/Fusion-v1.0.1.zip
Im still pretty new to cnc, Duet controllers and RepRap firmware so i cant say how perfect it runs but it works well on the jobs ive done already.