Legal tool number range? That is pretty much defined by you, or the tool changer. But there no hard rule to any of it. For instance, my ATC is a 16 pod geneva drive carousel. Tools 1-16 occupy the ATC and if 17 and above it called out, my M6 script goes into manual tool change mode. VERY flexible. Since I know my tool changer only holds 16 tools, that is the number I hard code in the M6 script.
Steve