You have posted that method more time than I care to remember. You are the ONLY person I know if that even considers that method on a perofomance camshaft.
You can't use that method on stock Z/28 chevy let alone a 310o cam ground on 106o
It DOES NOT WORK on all cams. Do you recommend 3/4 reach plugs for ALL chevys? It could possibly cause any less damage
You adjust the valves on a 1969 Z/28 just once, and you learn to stop using a method that only worked on flatheads, and should have been abandoned with the invention of the rocker arm.
LINK; Valve lash 30-30 Duntov