12 Jun 2019
Using two 27" monitors now: one Iiyama (3840x2160), one BenQ (1920x1080). The first has way higher DPI. To compensate, I use fractional scaling (175% and 100%). This needs to be enabled for X11, requires Ubuntu 19.04:
gsettings set org.gnome.mutter experimental-features "['x11-randr-fractional-scaling']"See here for more details.