The dialogue you show in your screen shot is for the default setup of a zone.
I just tried and for some reason the setting of the zone stamp parameters in there seems to have no affect on the new zone you are creating - not sure why.
I assume that these should be set as the default values but they are not.
You want to go into the zone stamp settings - with you zone stamp selected open the settings dialogue (CTRL+T)
Then you can change the settings for that selected stamp.
You will also need to set the 'Default' settings for the zone tool.
Then best way to do that is to ALT-click on the zone stamp you just altered.
Or just open the zone settings dialogue without a zone stamp selected and make the changes you want.
Save a favourite for it so it is easy to go back to those settings if ever you change the defaults again.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11