Road cranks' chainline?
 

Anyone know what the chainline of a road double is? say, with a 109 BB spindle. I'm thinking about JIS square taper cranks, like 2000-2004 Shimano Sora, Tiagra, 105... that sort of thing.
I'm feeling that 42 mm in not achievable, after looking at a 105 earlier.

Also, what's the shortest spindle that they work with (not hit the 68 mm BB shell)? 109? I've never heard of anything between 109 and 103 being made, and 103 is probably not going to work, even if I could find one. I think Shimano don't make anything under 109