So, my startcode suggestion would work - If I do
G90
G0 X0 Y-5
G92 X0 Y0
it sets work coordinates accordingly, and a
G0 X0 Y350
results in this:
At least in Cura that would be feasible - in Luban I did not find anything for inserting custom GCode…
Have written to Snapmaker support, let’s see what comes out.