There should be some tool gauge setter (looks like a tool, but it has no cutters, it's monolith with holder and it's measured and has it's lengths and diameters marked on)
U can also muasure some tool length from the spindle front edge.
If u have touchprobe length calibrated u can recalibrate laser gate by making test cut with any tool, then checking how high is Ur test plane, add or substract the differenc between ur programmed and measured height. And then use corrected tool for gate calibration.
This will make all Ur tools and gauges calibrated on the same surface.