Cool, I like how you show the different configs....interesting results too (the single fan config they have in the manual is the worst, lol).

What does your board say for fan RPM on those YLs? I have one here and it's performing identically to the D14SL-12 in CFM, dB, and RPM (says D14SM-12)....I think you may have three of those (they're quiet, unlike the SM).

EDIT: and I guess I got lucky....I started using positions 2 and 4 right off the bat.