My needles are always within the previously noted settings. If you are having this much trouble I would:
1. Check the Rod, if it was broken in to rich for to long, it may be have to much wear. RB's like to be broken in hard, never easy and bloody rich.
2. Check for Clutch, Do not worry about what springs everyone else is running, I run two heavy and one medium springs so I can get the bottom set the way I like it and so the needles work the way I want.
3. Tank fuel lines, Clutch LOL
My B9 is running like a Raped Ape. Just like all my C6's...it is just an awesome motor.
OD 77T is my plug of choice.