How far does a real grabiron stand off a typical body?

[nkalanaga]

That's the MINIMUM diameter.  They don't give a maximum, so one inch or a little larger would probably be acceptable. 

[Maletrain]

Real grab irons that I have measured were either 3/4" or 1" diameter.  Of course, 1" is still only 0.00625" in N scale, and that doesn't account for paint.  Frankly, I don't think I can see the 0.00075" difference from scale to the 0.007" wire that is available, though.  Now, if we could just chemically brown, as well as blacken that wire...

[mmagliaro]

Real grab irons that I have measured were either 3/4" or 1" diameter.  Of course, 1" is still only 0.00625" in N scale, and that doesn't account for paint.  Frankly, I don't think I can see the 0.00075" difference from scale to the 0.007" wire that is available, though.  Now, if we could just chemically brown, as well as blacken that wire...

My dome grabirons (which spawned this question) are made from .006" wire.  Detail Associates makes such a thing.  My photo in the 0-6-0 project thread is mislabeled.  It says I used .008", but that is incorrect.
As for chemically "browning" things, you can.  Jax Industries makes some chemical treatments that will create a brown finish rather than black.