which 6sn7 gives the most air??

bopper,
Go to head-fi.org and read The Reference 6sn7 Thread. They list all the 6sn7 tubes and pretty accurately describe how they sound.

I have collected just about all the best 6sn7 over the years.
Top end air, Tung-sol round plates or Sylvania 6sn7w tubes.
The Ken-rad VT-231 staggered plates have great bass and have more of an airy midrange than treble.

The Sylvania 52'GT(bad boys) are beautiful sounding tubes and probably my favorites. I know everybody loves the Tung-sol, but IMS the bad boys just sound perfect.

The Brimar CV1988 6sn7GTY are really nice too.

  

Bopper,
Make sure they have three holes in their plates to be real . Sylvania made 1952 6SN7GT tubes with two holes in the plates, but they are not bad boys

The Ken-Rads either clear or black glass sound the same to me. Most importantly is make sure they have staggered plates those are the good ones.