The main obstacle to SBS is the reduced screen width.
if you are designing your SBS scene for a 16:9 screen size in Landscape Orientation.
There is no loss of screen width.
you create two full width full size Scenes, then Scale each eye view by 50 in width. and place them Side by Side
So you are taking the Full Width, and just Squishing the width , Not Crop it, nothing gets cut away.
it's like taking two sponges, you squish the sides together so the two fit in the same width as One, and then you can later stretch it back out and both are the full width again.
Nothing was cut away or removed from either sponge, it was just Squished to fit a smaller width.
in the VR headset or 3D TV or 3D Projector
Each eye view is then Stretched back out to Fit the Full Width.
This is why
@Calgon wanted to use an 8K screen.
then Each 8K eye, is Squeezed down to a 4K width.
you get two 4K scenes Side by Side
you can do the same and Design for a 4K screen, then you get two squeezed 4K screens squeezed down to 1080p Screens Side by Side
When I did my Scene for the Portrait Orientation, then Yes, the Sides of the Scene are Sacrificed.