Here's a rule of thumb that has worked for me for 50+ years- - - -turn the lash adjuster down with your fingers or very gently with a screwdriver until it gets snug, back off 1/4 turn, and lock the nut down. It might be a little noisy during warmup, but it won't be too tight.
I just noticed your location- - - -I spent about 5 years living in Merced and running a 24-hour diesel truck road service up and down Highway 99, then I was a maintenance man and pipe welder for E&J Gallo, all in the late 1970's.
Jerry
