Upgrade StorageTwo Firefox profiles.
I know that you have closed the discussion about large libraries & firefox - but, has lucisandor thought about creating two firefox profiles? While you can't open two at the same time in Firefox as easily as you can in Chrome, you can ( http://kb.mozillazine.org/Opening_a_new_instance_of_Firefox_with_another_profile - windows. or https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles#w_starting-the-profile-manager Mac )
Between those two, you can get 2 profiles set up & choose which one (or both) you use.
Between those two, you can get 2 profiles set up & choose which one (or both) you use.