" Well, basically Z value depends of the territory shape, if it's plat or bumpy, are there mountains or not. If it's plat, more or less, you should be fine with +-100 from the basic value generated from /loc. You can add bigger to be 100% sure that when someone ride the strider, fly with wyvern, will not leave your zone. "
Take a look on the middle position. If you set the min/max too low, when you do a step you will leave the zone (for example, mount the wivern or ride the strider - the Z is higher, boom you are not inside the zone anymore).