When a lifter is resurfaced, its length is only changed by a few thousandths. All that's actually done is re-establishing the slight radius at the bottom to duplicate its original shape. That radius, along with the slight off-center position of the lifter VS the lobe center, makes the lifter rotate as it runs. A stovebolt rocker arm adjusting screw has 20 threads per inch, so that changes the effective pushrod length by .050" per turn. Refacing a lifter will probably use up less than half a turn of the adjusting screw.
Jerry
