Have to agree with it depends and John S pointing out some of the reasons. If it setting up a part on the deck that is NOT going on a preset jig I set up to the material and then add offset to get the bit where I want it (usually .5 to .75 diameter of the largest bit being used) unless there is a built in offset in the project or I have to put in a larger offset due to needing material edge that needs to be remaining. I use G55 to G57 for most of these and they get changed as needed. For Jig stations where the Jig has been placed and is squared and the material is a fixed to the jig; then I use the preset G59P# depending on which station I am using (start at P7). This probably is as clear as mud and hope I am not just making it worse.

Tool offset I deal with in my CAM programs so that issue does not become a problem when dealing with the machining side of the item. CAD wise it depends if I am planning to offset the item and we are back to same issue as above. I tend to work from 0,0,0 in CAD and then adjust once in my CAM program IF I am going or need to.

Michael