Found at another instance, a fellow user suggesting a way to use the FULL width of our modern laptop/desktop screens.
A big pet peeve of mine, if you know me. (got mine running and quite happy)
Here's his/her suggestion :
"Another tip is to use the the browser addon Stylus and then add a userstyle like https://userstyles.org/styles/154943/mastodon-variable-width-variation to make it fill whole the screen. You have to edit the userstyle to include your instance though. "
This one seems to have one advantage compared to my own setup -- there's mentions of Columns being adjustable in width, which is a nicety I have only found in ONE client for Mastodon so far --> Whalebird.
https://github.com/h3poteto/whalebird-desktop/releases/tag/3.0.0