Alan,
Continental ground baits, although loosing some popularity lately, are a fascinating subject.
Typically, the ready to use mixes are formulated to provide a certain degree of; strength, colour, texture and binding power that you require. Then there are the base mixes, colourings and additives both in powder and liquid form that can be used to make a bespoke ground bait to cover certain situations.
The Sensas factory at Fontenay/Eure, near Chartres is well worth a visit and is really informative. I learned that typically a specific mix can contain up to 22 different ingredients and to understand them all one needs to be a chemist
For repeatable results I would highly recommend either van den Eynde or Sensas mixes as these are carefully controlled in their manufacture and conform to rigorous standards.
If I ever get the time I have been thinking about writing a short series of articles on groundbaits but I wonder with the adveny of so many pellet and pastes being used these days if there would be any interest?