Just a suggestion for docs ...

[dbarnes10]

It's important for modes that actually use cloned/created left& right cameras - eg "two displays" - that the user code not use the shortcut Camera.main to access their (main, mono) camera.

Using Camera.main results in undefined and possible buggy code because the cloned/created left and right cameras are also tagged as "MainCamera".

This tagging is necessary so suggest documenting this "gotcha".

Otherwise a big thank you for this terrific script!

[Vital-Volkov]

OK thanks, I'll make docs for release.
I set the main tag for S3D cameras only because the main camera should be off in 2 displays mode as it eats fps even without rendering the scene but some Unity's example scenes are not working when no enabled camera in scene with main tag.