Is there some way to change the default model units on new documents to something other than mm? Also, could someone explain to me how “Page” units are used? I don’t seem to find any documentation on them.
Not until a template file start up system is put together like Rhino for windows has. Then choosing a different unit/tolerance template will be possible.
Page units are meaningless until the Layout feature is added to Rhino for OSX.
There is no formal Rhino for OSX documentation yet.