Most likely this has already been explained here and I'm just not smart enough to find it …
Anyway, I created the Mark2 magnetic tool changer for the Ultimaker2. Now it's time to add a third head. For doing this we might replace Ultimaker electronics and our customized firmware by Duet3D. Like before offsets and tool changes should be handled within the firmware. We actually attach and detach head 2 or 3, with a z offset, while the standard head always remains in place. Extra heads are parked in two corners.
So, what coordinate space I'm in when e.g. switching from T1 to T0? In other words, do I have to adjust the docking position within tfree1.g using the T1 offsets?