OmniOutliner 4 fullscreen behaviour

I remember having a tweak on my iMac that changed the full screen behaviour of OO3 to not use the whole screen, but only part of it (which looks much better IMO).
I’ve tried to search in the old forums for something, and I found an apple script but I can’t make it work (and I don’t even know if it does what I wanted to do anyway).
Does anyone knows what I am talking about? Making OO occupy about half of the screen, but centred instead of the whole thing?

On a side note, is there a way to make the bottom line not be completely at the bottom? With a big screen is silly to focus for hours sometimes on a single line at the bottom of the screen.