Probe Z offset

Apologies for the use of improper terminology, newbie here. So, I have a PrintNC machine with Probe Basic. For the most part the setup has been intuitive, and most of the questions i've had have already been answered here. The one thing I'm a bit confused about is probing, I have a tp06 probe, and I've been using it to find corners, bosses, bores etc. So one of the settings is the tip diameter of the probe, which is perfectly clear to me as to why it's needed. The one thing I cant figure out is, isn't the height of the probe also needed? In my mind, i can bring the spindle (no tool) down until it touches the spoilboard, and record the Z height at the point (Z0). Then I cant put the probe in the spindle, and lower it until the spindle touches the spoil board and record that Z (Z1). From there the probe offset is Z0-Z1 (or the other way around), My question is, where do i configure that probe offset? is it a variable in the .var file?

I don't know if Probe Basic does it differently, but the probe I use with the Axis UI is configured as a tool in the tool table. The length offset then gets applied like every other tool