Has anyone programed the interface to display rear time extrusion rate in mm/s in the same we see printer head movement?

I push my setup pretty hard in a production environment and I would like to calibrate E steps, pressure advance, etc at the same extrusion rates in a given model. I know I can estimate these rates from the G-Code, but I would prefer to monitor the real time extrusion rate during the print.

I would like to use my z probe to define a bed level mesh to compensate for a large crooked bed. This z probe is physically installed and removed as needed and the routine is typically ran daily. I also have a Z endstop that I would like to use frequently (between prints) to keep a tight tolerance on the first layer height. Is there a good way for me to do both?

I was previously using a ChiTu board that did this successfully, but I haven't found a good way to do that with the Duet yet. I noticed that the ChiTu board used the same pins for the z probe and the z endstop (they were wired in parallel).

Has someone pulled off a configuration like this yet?