centrifugal advance springs
 

I know this subject has been run into the ground but I'd like to know how far off I am on my interpretation.
Mild pinging happens on part throttle after lock up in 4th gear. RPM ranges are 1000 to 1600. Stock 350 with rv cam. Two blue springs, cannister nine turns out and lockout at last notch, providing 12 additional vacuum advance degrees. Initial at 12. I would think that under these conditions intake vacuum would be low, around 5, providing minimal vacuum advance. I'd like to leave initial at 12, it seems to have better power there. Does this mean there is too much centrifugal advance? Would it help to go with one blue spring and one stock?