Ok looks like I've got it to work by adjusting the G31 Z in config.g in a few iterations.
Never got that G92 Z0 to work always seemed to be reset after doing a home.
But it may be me being stupid as a newbie

Really liking the board, firmware and web interface so far, you've done an incredible job!

Hi,

As a delta owner coming from Smoothieware I'm having some trouble wrapping my head around setting up my Z-probe and calibration.
So I was hoping for some help from the experts here.

My machine has magnetic arms which I use to swap between my effector with Z-probe and another effector with my hotend.
(to keep the hotend light and compact)

I can succesfully run auto calibration and mesh bed compensation however don't understand how/where to put my probe/hotend Z-offset.

My Z-probe is configured as:
M558 P5 X0 Y0 Z0 H40 F300 T2000 R0
G31 X0 Y0 Z0 P500

When I manually move until the Z-probe is triggered Z=20.70
When I swap to my effector with hotend and manually place it to touch the bed my Z is 18.73

In smoothieware I normally place the effector to touch the bed then do:
M306 Z0
M500

Which stores the offset in an override file as:
M206 Zn.n ; (n.n is measured offset)

I'm trying to wrap my head around how/what to do this on my Duet Wifi (which I like much more!)
It seems G92 Z0 defines the current Z as Z=0, however this does not seem persistent after homing or a power cycle.
Or should I manually calculate a rough offset and place it somewhere in th config/bed file (where?), and then rely on baby stepping for fine tuning?

Probably a simple thing but I'm just a bit confused for the best solution, any help?