I have 29" Wide monitor (21:9). I usually have 2 programs on it side by side. I use keyboard shortcut Super+Left/Right.
It works great except I would prefer to split screen 60-40 not 50-50 (or maybe 70-30, it will need some testing). The reason is one of the programs is code editpor for which I need quite a lot of room (but not whole screen) and the other is Chrome (or Firefox) Developer Tools, for which I don't need so much space.
I am on Ubuntu 17.10 and using multiple (4) desktops and 2 monitors, but I think it is not relevant.
Thanks a lot.