Can't offer any ideas about fixation, but as to mounting media, I've
been very pleased with MOWIOL.  If you've not come across it (Mowiol)
before, you might check out the protocol page at our site.  The direct
address is:

http://bic.usuf1.usuhs.mil/protocols/SamplePreps/mowiol.html

PS - I never store processed slides cold.  Just keep then at room T in a

"dark" environment, such as the cardboard slide trays used in most
histoprep labs.

MRA