The product I have is called "acrilic retarder" of this "Talens" (or "royal Talens"
trademark from Holland...
My mother suggested and gave it to me (she paint on canvas), and I don't know if there are better products properly for modeling, I must think so.
If there is perhaps works better, this one if use too much has the inconvenient of reducing the grip of the paint on the models, so is good only for dioramas and static modeling, for wargaming I suppose isn't so good because probably the paint would tend to come off from the parts subjected to the touch.
Another difference using it, further to slow the drying, the acrilic works more similarly to the enamels or even like oil colors, well somehow, and this can be usefull or not depending by the technique used.
Finaly when the drying is so slowed is necessary a painting method that allow to avoid to touch the miniature, that is not always necessary normaly.
Leo