tunefs average file size?

[Laurence Sanford]

I've been looking at some ways to make fsck and general day to day 
functionality faster with a large file system I have mounted on one of 
my machines. I see a setting for average file size in tunefs. What I'm 
wondering, is what affect this would have on day to day functionality 
and fsck processes when they have to happen. The default file size looks 
a little on the small side (I suspect it's the size in bytes?) 
considering the contents of this fs are all audio and video files 
averaging 5+ megs each. Any pointers on where I can find more 
information? The man page for tunefs doesn't go into much detail, nor 
does newfs.