with leaded solder, around 650F I think, maybe 700. i just know where to turn the dial to, and my station's labels are in watts, not temps. it's hot enough to flow the metal and move to the next joint very quickly. the downside is that solder gets sticky real quick at high temps and you have to constantly clean the tip even if you turn the temp all the way down (recommended for longer tip life) every time you set the iron in its holder. that's why i like to have a whole row of components lined up and go down the line, bang bang bang, etc.
you're probably just going to have to experiment with some trial & error to find the temp that makes you happy with your new iron.