If it were me. I'd do as the article says. Find what it likes initial. Then find what it likes for total. And go from there.
Instead of messing around with welding the slots and all I'd buy the plate from FBO I think it is to make tuning the curve fast and easy.
Most of my cars I set the dist up with one light mp spring and the lighter stock spring. Brings total in about 2100rpm and has worked well for in the past.
You sure the pinging isn't a lean condition?
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