So just an update here and request for some help!
I ended up grabbing a Dell Ultrasharp 27in 4k. Its 163ppi and I tested it as a 2nd display on my iMac prior to moving across to windows and I was able to tell line weight difference up to 0.18mm
However, for some reason now that I am on VW on PC, lineweights do not show up until 0.35mm! Could this be an issue with the settings? WhenI zoom in and out it seems to display the thickness difference, however, once I move the cursor the line weights go back to all being the same. This is driving me nuts.