It was pointed out that if the mixture is too runny it will make the bees wet and sticky which is not a good thing.
After pressing the mixture into the end of the queen cage, place a small square of wax paper on top covering the candy before stapling the screening closed on the queen cage.
This recipe is from the book Queen Rearing & Bee Breeding by Laidlaw & Page.
Chapter 5: The Care and Use of Queens:
Sugar Syrup: Powered surgar mixed at 1:3 ratio
Stir powdered sugar into syrup
Add small amount (drops) of glycerine
The mixture should not be hard and dry nor soft and sticky.
Store in an airtight container in a cool dry place.