it's still a bit convoluted but I guess it's usable now:
I uploaded a new version to Patches.zip (Build 1828)
you need to also copy over the new editor (if it says XED 3231 in the window your good)
- enter mode 7 for map info (this is only needed to see your change)
- now if you use the command line command:
SKY city3
- you will see the info change (Skybox:city3)
- in the preview (play command) it should use that skybox
(and you don't have to bother with the scripts later, in fact this overrides any other sky name set in script)
(skybox preview in the editor is still broken -- I spaghetti-ed myself into the corner 😔