Monza, the 100/2 is a stellar lens, one of the best in the whole line.
Is is not much bigger then the 28/2. (If I were you I would sell the 100/3.5, if you have to. It is very good and small but the 100/2 does everything a little better.)
I bought the 28/2.8, much smaller and very good IMO.
I have got 12 C/Y lenses now, 3 zooms included.
I would never be able to choose between the 85/2.8 and 100/3.5.
I like them both.
There are 3 on my wishlist but I am in no hurry the 21/2.8, 60/2.8 Macro and the 85/1.4
BTW Your Macro-Planar S 60/2.8 does not go to 1:1, right?
Can you tell me more about the difference?
Looking forward to your comparisons!