Andi

Two (slightly different) suggestions regarding your question.
1    We used to use a fast red substrate and coverslipped using a locktite
engineering adhesive which we cured with UV light, this works well and
produces a dry slide which can be filed and stored. Unfortunately, I am out
of the lab for the next week and cannot let you know at the moment the
product code but will let you know as soon as I can if you're interested.
Alternatively
2    We have recently started using Vector Red (surprisingly from Vector
Labs) this produces an insoluble bright red colour and we coverslip with
resinous mountant on a Leica coverslipper.

I appreciate these suggestions do not directly answer your question, but be
provide useful aternatives.

Good luck

John Auld
Dept of Immunocytochemistry
Royal Free Hospital
London