Quantifying feeler gauge drag

[Semper Gumby]

I go with a fair amount of drag.  But the acid test for me is if I can get the next size up feeler in between the valve stem and the rocker.  If I can push the next size feeler then my adjustment is not tight enough.

Also, I tighten the locking nut on the rocker slowly and re-check the clearance as I do so.  This is my concession to my OCD!   8-)