Don't use water as a reducer it makes it take too long to dry.
Use Auto-Air Reducer 4011 use it 2:1. That's what I use and I don't have any problems.
Or you can make you own here is a recipe:
Makes 20oz of reducer...
12oz Distilled Water
4oz Denatured Alcohol
4oz Ammonia Free Window Cleaner
10 drops glycerin
In case you don't want to make 20oz of reducer,
the mix ratios are 3:1:1:drops Water:Alcohol:Window Cleaner:glycerin
with this try 3:1 or 2:1 at first (paint:reducer) and see how it goes for you if you and if you
have to go for a 1:1 mix do it, it just depends on the colors you are using.
Good Luck
Iccemann