Just a reminder, you probably want to make these changes to line up with your shop practices, right? Sometimes when you do this you are getting away from drafting standards. Just saying . . . I always got questions about the funny symbols in the hole countersink etc., so I've changed mine too.
You can create a custom file for the callouts and locate it wherever you want, even on a server so everyone can share. Make a copy of the original file and edit it the way you would modify code by commenting out the original line and putting in the new descriptive callouts. Then under tools/options/file locations/hole callout format file/ point to the new file. To revert to the standard SW file, jut redirect that setting.
--
Hardie "Crashj" Johnson
SW 2011 SP 4.0
HP Pavillion Elite HPE
W7 Pro, Nvidia Quaddro FX580