Since you don't know what you are looking for on smoke, always start out on the rich side. It's hard to describe how much you are looking for. I would describe it as a thin trail, but constant. It's really a trial and error thing. This is where your temp gun will come in handy. Run it for a minute or so, note performance/smoke and temp it. Then lean it out a little and run it another minute or so, note how much smoke and temp it. Repeat this until you are happy with the performance and not superhot. Note how much smoke this is and remember it.

I get worried at about 280F and will richen it up some. But some engines like to run hot, that's why there's no magic number. The alloys used in these engines start losing their properties at about 300F.

Here is Jared Tebo showing you how to tune on youtube. This should help you. Watch this, mess with your nitro vehicle and do what he says, then watch it again.

http://youtu.be/iwzcWLKKU0I

This is backwards from how I tune (he does HSN first), but shows how much smoke you are looking for.

http://youtu.be/oSmMzpZM_As