Touching off a diamond shaped insert tool on Z axis on lathe

Thanks to this great forum, I have been able to get up and running with a Sherline Lathe and LinuxCNC. Just ran into a question I haven't been able to track down myself. When I am setting up a tool table and touching off different tools, so far, all of them have been straight forward. However, I just started using a diamond shaped insert tool and have it in position 6 (perpendicular to the stock). Touching off the X-axis is straightforward. However, what is the proper way to touch off the Z-axis. Do you eye ball the tip? Or do you touch off the left side diamond that is 90 degrees from the tip you will be using to do the cutting?

If you're using a CAM program check what it expects.  Or if you're going to use a CAM program in the future, try to get a sense of what they normally do so it doesn't feel 'weird' later on touching off in a different way.

F360 generally uses the left side of the tool (or right if it's a back tool) and you have to measure & define the insert pretty closely if you want to hold size when cutting both with both sides (diamond tool, radius groover, button cutter, etc.).  Good luck if it's a hand-ground HSS job.