Well, here is some data from the Parametric Table thread that might help.
Parameter X_Actual is defined as X_Usable + 2*YZ_Thickness + 126mm + 180mm
From this is stands that the minimum X position that the tool can address is 126mm + the thickness of the YZ plate from one side and 180mm + the thickness kf the YZ plate from the other side. Assume that “side” in this case is the outside line of the belt holders.
The Y_Actual breaks down from a few more parameters to be 149mm from the front edge.