curious about valve lash setting/check

Gentlemen, if any of you are still here: started her up tonight and it sounds like a child's teeth on a cold winter day. when I adjusted the rocker, I felt the slight drag, then went about 3/8 of a turn and locked them down. if I was to guess, I'm thinking I need to crank them down a little more, but I don't like to guess, hence....asking the wise/knowledgeable group. if I should tighten them down, can I just add a half without going through the rotation of the engine (as previously), or what would you suggest I do? thanks again, you've all been very helpful.