I always use compact mode regardless of screen height but one of my screens is 600px high, I need compact mode for it. The web is unusable without those few extra pixels I gain from compact mode. I also set layout.css.devPixelsPerPx to 0.75. I keep telemetry enabled too because I know some of the features I need are in danger of being removed if they disappear from their statistics but it seems that it doesn't help at all if they remove them anyway. If this gets removed I'm turning off telemetry, I'll have no use for it anymore.