Justin, I love MM enamels. Drying time really depends on what you use to thin it. I use two thinners for MM: Lacquer thinner and Mineral Spirits.
Lacquer thinner will cause these paints to dry much, much quicker. You could probably paint over in an hour or two. I use Lacquer when I'm laying down a primer coat, and mostly on military aircraft where a good finish is easy to obtain.
Mineral Spirits extend the drying time greatly. This is the thinner of choice when painting model cars, as it allows the paint more time to even out. Gloss paint jobs with enamels and Mineral Spirits are often set aside to cure for a week or so.