Head Shift - Looking for information on how to use this command

Hello,

I’m new to CNC and G-code and learning on the fly. I have a CNC table with 3 devices/tools attached to the Z axis (laser, Marker and router). Laser is to the left of router about an inch and marker is in front of router about an inch.
I need to set this machine up so a non cnc person can just load their job up, select which of the 3 tools they want to use and run it.
From what I’ve read I need to use the G10 L20 head shift command?
How do i do this so the operator can just select which tool to use?

I’m currently using mach4 and vcarve pro.

Any and all help is appreciated!

Thanks!

I have a similar setup (but with linuxcnc). In my case, I put the correct offsets for X, Y, and Z into the tool table, so I could just use the usual M6 and G43 commands to choose one of the three “tools” and load their offsets.