Yes, that is the projection that is set in the the default render script. You can change projection in a custom render script if you want to. But for most cases the best way is to keep things between -1 and 1. The numeric precision is very good in that range.
I need a larger range, pehaps -10 to 10.
How would I implement the above into a custom render script?
(is there a tutorial somewhere on how to modify Z order range in a custom render script?)
You do know that these are floating point values? You can have one object on 0 and one on 0.0001 and one on 0.0002 if you want, and even way more fine grained than that.
But if you really want to change the render script:
Copy the built in render file and script to a location in your project.
Alter the render file so it refers to your script copy.
Set the bootstrap render file in game.project.
That’s it, now you can edit the render script. You need to change the near and far values if you want to change depth range.