Running KSP at a high resolution with UI scale set to 150%, I find the KER text small and difficult to read. How hard would it be to make KER read the scaling from the game's configuration and use it as well?

Thank you very much! Feel free to close this, unless you want to keep it as a reminder.

I believe if you go into the VAB and click Settings on the KER windows you can increase the 'Gui Size' for KER. This applies to in-flight as well. I'm guessing this system pre-dates the KSP stock UI scaling. Something to look into fixing in the future but the KER-specific setting should solve your immediate problem.

Oh the Gui size can also be changed by adding the Misc>Gui Size readout to a Flight Readout section