Does it really default to the single-column layout? I've been using it for months now on 3-column so I guess I must have forgotten switching over. This is what I see on my desktop:
I 100% recommend switching over to 3 columns; not nearly the space-waster. The setting's in https://plus.google.com/settings, ctrl+f "Restrict stream to single column layout on all screen sizes" (the design is especially bad on that page).
https://imagebin.ca/v/2tORL2z4J7LW
Seems like an awful waste of space.