I had a problem with my 1st layout 15 years ago with either the 'wet water' and/or the diluted white glue mixtures 'tarnishing' the rails (a non-intentional weathered look). I would like to avoid this from happening again. 1. What is the preferred ratio for ballast adhesive? 50/50 white glue & water or something else? 2. How about "matte medium instead of white glue? 3. For 'wet water', would a 90 or 99% isopropyl alcohol bet a better 'buy' than the 'watered' down common 70% found anywhere? This is N scale Peco code 55 if that matters.