Windows 'Magnifier' can be surprisingly effective and quite configurable to the way that you want use it (Full Screen, Lens and Docked modes). ... esp for even 1080 on a 13" screen (let alone 1800!).
 
Quick and easy (try it):
Direct Full Screen zoom in = Win+"+"
Direct Full Screen zoom out = Win+"-"
 
Else to start the interface panel (and right-click open from Task Bar):
Win 10: Start > Magnify  (I dunno if Win still takes you to 'Metro'(?))
Win 8: Win > Magnify
 
[UPDATE: Actually even Win+"+" invokes the magnifier. It'll be in your Task Bar when you zoom back out (with Win+'-')]

These are GREAT suggestions folks! Thanks so much!

In Windows, the only solution / workaround that works reliably for me is to run the Hi-Res display in sub-native resolution.
 
Font scaling just isn't consistent across applications. 4k screens on a 13" laptop is just.... crazy.

I'm hoping that when the final version rolls out, the scaling issue will be fixed. In the meanwhile the magnifier suggestion worked spot on ... I just needed the buttons large enough to make changes ... so it was a good work around.

But on a 13 inch screen, resolutions can get darn right silly. :D