Jimmy,
It depends on what you're using for reducers. There are slow, medium, and fast reducers. There are also clears that are faster than others. Sometimes the paint will appear dry on the surface after only minutes, but I like to give 15 to 20 minutes between coats to ensure that the solvents have gassed off. If you trap solvents under fresh coats of paint, they will eventually come out leaving solvent pop's, those micro pinholes all over the surface. The DT860 I'm using right now is for colder weather spraying (it was only about 60 degree's today). DT870 is a medium reducer and DT880 is slow reducer for higher temps, around 80 or more. If it was that warm I'd be using DT880 to avoid dry spray or a host of other potential problems.
Jeremy