I'm just in the starting phase of marbling and my experience is close
I first tried out oil based paints on MC size - but had a lot of
trouble and small control of pattern.
Then I got hold of some samples of CMC and tried out water based paints
(which I made from Caran D'Ache aquarelle "chalks") and different
amount of syntetic oxgall. Suddenly I achieved something that looked
much better and felt that I actually could control the patterns of
several colours much better - even if the results were generally
According to the following technical datasheet for the CMC it should be
possible to adjust the rheology quite much. I made the size to a
viscosity similar to a thick coffee cream - maybe a little thicker.
So... to me CMC seems to have some potensial. But as I said - my
experience is still close to zero. (But increasing!)