If your saying your using the up and down method make sure you know exactly where zero lash is and then don't worry about the amount of preload resistance I like to use 1/4 to 1/3 turn preload on 3/8x24 adjusters (24 threads per inch equal .0416 per one full thread so 1/4 turn equal .0104, half turn =.0206 and so on) Not all hydraulic lifters like or need the same preload Play with the amount preload on yours to find what you and your motor like
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
I like to use 1/4 to 1/3 turn preload on 3/8x24 adjusters (24 threads per inch equal .0416 per one full thread so 1/4 turn equal .0104, half turn =.0206 and so on) 
Not all hydraulic lifters like or need the same preload 
Play with the amount preload on yours to find what you and your motor like 