I don't have any issue with the session itself being shared. It's actually the desired behaviour almost all the time. I just don't want to be dependent on the frame sizing of a terminal no one's even looking at.
jbnicolai's method kinda solves this for me. The upshot is the set of windows is mirrored between both clients, but they can each be looking at different windows. You still have a problem if the other client is looking at the same window that you're on, though.
