Factory spec on new points was .022", .018" is the setting if they've been in service for a while, I would suspect because of erosion. I've also seen non GM literature years ago, like that from Blue Streak that calls out .016". If ya start nit picin' one or two thousands on an engine of this caliber then your a whole bunch more particular than I ever was or ever will be. Of course you want to be as close to the factory spec as you can get but between one or two mils on the points and a couple of degrees either way on the timing I doubt whether 99.9% of the owners could tell the difference in performance, power wise or in their gas mileage.
I've set the points simply by eye and the timing and mixture just by ear and again, barley noticeable difference in performance, but I’ve been messing with this stuff for nearly 60 years.
Denny Graham
Sandwich, IL

Denny G
Sandwich, IL