Measuring is the best way to avoid mistakes.
I forgot if they measure ball to bottom of cup or ball to top of cup (overall). But OEM LA ball/cup solid lifter pushrods are 7.50" while OEM LA ball/cup hydraulic lifter pushrods are about 7.21" or 7.23". The reason being that the solid lifter cup is deeper inside the lifter body than the hydraulic lifter. Then you have the variables of milling & decking.
The 7821-16 Comp Cams pushrods show 7.389", which is closer to solid lifter length. Measure with an adjustable pushrod or estimate the length using a known length pushrod. Personally, I prefer to have 1-2 threads of the adjuster showing under the rocker. Less load on the adjuster and you'll actually get a tiny bit more lift due to better geometry.
