The purpose of using glycerine/alcohol on flat skins is to keep them soft, which it does. Putting the mixture on one coat at a time allows the alcohol to penetrate the skin carrying the attached glycerine.
The alcohol evaporates leaving the glycerine in the skin. Soaking a skin in the glycerin/alcohol mixture would not accomplish this. When I am mounting reptiles I want the skin to be soft while I am mounting it and not drying out ( I live in Arizona). The Dynamite 111 is a water based clay glue and between the glue and the skin having one coat of glycerine/alcohol allows me a couple of days of fixing any skin alignment, ect on the mount before it dries. Otherwise it would be dried overnight and you would be stuck with how it looks.
It works for me. Just find what works.....afterall it is the finished product we are after.

Kerby...