Router bit length probe

[abowers]

Howdy all,
I'm looking at building a fairly large CNC router, and I'm thinking on using Duet Wi-Fi what for the high current stepper drivers. I've got some pretty big NEMA 23s in mind.

I would like to have a probe to determine the bit length offset; in other words, have a micro switch that the router pushes with the installed bit to determine the exact length of the installed bit, so that the user doesn't have to bother with it. Would G30 be the code to use?