The absolute best way is to set them with the intake off,when first assembling the engine.You want the pushrod to engage the plunger of the lifter past the circlip retainer in the lifter body.
This is how I did mine, rotate untill lifter is on base circle,install pushrod ,rocker and then adjust them until the lifter internals are depressed below the circlip inside of the lifter body,I also used blue loctite on the poly locks.
I then assembled the engine and broke it in,no further adjustments needed,looking back I would not hesitate to use red loctite on the poly locks.
For a hydrauilic lifter in a mild engine ,you should never have to adjust them again ,unless there is failure going on,they should never loose the adjustment in 100,000 miles,unless wear /breakage/stud pulling out of the head ,etc.
Unfortunatly this only works on mild hydro cams and only on the initial assembly of the engine,I would not use this method on a installed engine,only a fresh engine stand build.