Well spoken!! Practice!
I also use a 155 and 10psi might be a touch low for it to atomize properly, try it but if the paint spatters or spits raise it a PSI or so until it comes out as a fine spray.
And as was already mentioned close to the model (1" or less) and thinned more than normal paint. You;ll probably have to play with this until you get something you are happy with. an empty milk jug is nice to spray onto when you practice, lots of curves and flat spaces to get a feel for the technique.
And you won't need to pull the trigger back much if you want a fine line or mottle. Just a touch.
Oh yeah and in case it hasn't been mentioned yet, practice!!!
---edit---
and of course you will want to use the metal color cup, and not very much paint in it either. If it is a custom color you will be spraying mix it in the glass airbrush bottle and put a top on it and keep pulling out of that to feed the color cup. You just want enough paint in it for a few squirts.
Good luck to you!!!