The issue is that I don't know how many GB it still really needs (even if I saw the value of 160GB globally on some sites)

I had
120GB free few weeks ago on my "Windows C:" disk
with Armory already uptodate and now I have only 4Go on this disk ...
My %APPDATA%/Roaming/Bitcoin directory is currently around 117GB
For me, the blockchain itself is about 140GB, not including chainstate. Back of a napkin math says it grows about 4GB a month (and this may increase) You may want to run something like
windirstat to help identify what is using your disk space.