On my desktop, admittedly a 29" Ultra wide screen, the content looks awkward in the middle of a lot of white space.
Instead of using physical units, cm etc, I use percentages, e.g. left column 10% middle 78% right column 10%
The 2% is deliberately left out to take into account screen resolutions and give things a little bit of room to
adjust themselves.On this screen it appears as though the left and right white space is about 30% each.
Cheers.