I think you can't go below 96. I tried with win 8/8.1 to get them working better on a 800x600 display. Anyway I can't understand why you are looking for the same thing on a big 1980x1200 display. Where's the point?
For a resolution of 1980x1200 with a 100% scaling should be a little bit less blurry. I tried 144 scaling value(being the recommended) on 1920x1080 and it looks bad, texts were larger and some apps didn't fit.