[Cherryville Chuck]

Once you have the bit to the bottom of the collet there is nothing more to be gained. So if you remove the collet and measure it's length then that is the minimum insertion length for the bit shaft. It will be somewhere between about 19 and 25mm (my DeWalt 610 collet is only .7 something of an inch long). That's a clever little jig Harry made for keeping small straight bits from falling through.

 

[Cherryville Chuck]

Peter if you look at the MC you'll notice that the screw that clamps it to the bit is near the top end of the MC. This is different than the slotted collet in a forcing cone type design that is the norm for standard collets. One of the reasons for making sure the bit is at least to the lower end of a standard collet is to ensure you don't damage it by having it squeeze together with nothing to restrain it from going too far. As long as a bit is past the tightening screw on the MC a little ways then it shouldn't damage the MC. Certainly the more shaft inserted, the better the holding power would be but if you stopped at the 1 inch insertion mark that should be good enough.