What is "71s"?  That doesn't register for me.

Think about row spacing in terms of your whole management system.  You seem to be thinking along those lines, and I think you are on the right track.

I didn't think about the benefit of narrow row spacing for better weed control. And that would be a definite plus for going to narrower rows. 

That one article that I posted showed yields with twin rows in 36"  showing virtually the same yield as 36" in single row.  I found that interesting.  So, there must be something else going on there.  

I think you are on the right track.