I try to use Gunze paints as much as possible, they are fantastic IMHO!
Drying time, like reggie said, depends on where you live, but a couple of days is your safest bet.
I thin mine with a mix of Iso, and distilled water, just my personal preferance, but they will thin with Tamiya thinners extremely well.
I wouldn't apply a wash over them without putting down a barrier, like Future, before hand.