@mikeabuilder as we have a new screen under development, we don't plan any further development on PanelDue except for bug fixes and essential updated to retain compatibility with future firmware versions. So I think your choices are:
Modify PanelDueFirmware yourself. Once you are set up to build the project, it should be straightforward to increment the displayed tool numbers.
Number your tools from 1 in RRF. Then configure a post-processing script in PrusaSlicer that replaces T0 by T1, T1 by T2 etc. You will probably need to replace the tool number parameter in a few other commands, e.g. M104, also G10 with P parameter if PrusaSlicer uses that.