Hi Ro,
Well, from reading a few websites, I can tell you that information is definitely sparse when it comes to this airbrush. But from what I've gathered, a #1 needle will spray a line from 1/64" - 1", #3 is 1/32" - 1 1/4" and a #5 is good for 1/12" - 1 1/2" spray patterns.
Now, because it is a syphon feed airbrush, it's going to need slightly higher pressure to work than a gravity feed. For a fine line, with a #1 needle, I suggest starting out at 15 PSI and adjusting it from there. I have an Iwata Eclipse BCS which is a syphon feed but I only have the standard needle (which I belive is a 5mm - equivalent to the #5 paasche). For fine line stuff, I usually shoot around 12 PSI. I also have an Iwata Revolution BR, which is a gravity feed. I purchased an additional 3mm cap to do really small work. I generally shoot that between 5 and 8 PSI.
That should help as far as a guideline, but it's only a guideline.
-Fred