Tool probe location

I have a Hass VF-2 coming with the wireless probing package, and I'm trying to plan out a subplate including the mount for the tool probe (TS27 type).

The Haas installation manual says to leave at least 2" of travel on all 4 sides of the disk for calibration. Is this really necessary? If I use a 0.375" calibration bar, how close can the probe disk center be to the +x limit?

How close to the +y limit would you mount it?

Thanks!