pushrod length/measuring question

so let me get this straight i take the number 1 cyl to top dead center with both valves closed insert my checking pushrod,adjust it to zero lash with 1 thread protruding below the rocker,then i measure this and add 30 thou to the overall measurement for preload(this is what my comp cams paperwork says regarding preload with there lifters)i dont have a solid checking lifter,does this method sound right,also when i measure from the tip of the ball to the top of the cup,what do i add on for the other half of the cup,and when comp advertise there pushrod lengths,does it take into account the other half of the ball protruding from the cup?????????