Problem is that the gantry is already very low Geofrey, the bottom of the Z axis is only just over 50mm above the bed to start with. These machines were made to cut relatively thin substrates so no need for a high gantry. Have seen a clip on youtube where a guy had raised the gantry using a couple of aluminium blocks but it didn't look a great way to do it to me. First thing to do is get it up & running anyway, after that I can look at making changes if & when I need them.
Doubt it will get used a lot for any kind of signwork as I only work part time now & tend to do mostly vans these days.