What a curious crittur the airbrush are…
No, not everyone has a separate airbrush for acrylics, enamels, and lacquers. Some of us are that lucky, most probably are not, except for people with airbrush fetishes like Bill…
The critical key to using one airbrush for all coatings is simple in concept, sometimes maddening in execution:
CLEANLINESS
Think of clean as "surgically clean." It doesn't quite have to be that clean, but thinking of it that way helps achieve a sufficient result.
When switching from acrylic to enamel or lacquer, or the other way around, strip down and clean the airbrush completely, and allow to dry thoroughly. Nothing from the acrylic world should ever touch anything from the enamel/lacquer world, and vice versa.
As for tip dry with acrylics, a good acrylic retarder will solve your problem. A single bottle will last a lifetime, as you will be using about one drop per airbrush cupfull of paint.
Thinning ratios and air pressure are only learned by experience. Take all the advice and suggestions, find what works for you in that particular airbrush. Be patient. Expect to make mistakes. Learn from them. Try not to make irrecoverable ones on expensive kits.
Yes, it is another learning experience…