With any hydraulic cam you need to check the length with the appropriate preload on the lifter. This can be a little confusing ... Have the lifter on the base circle as you've done. NOW lets say (for example) that the preload requires 1/2 turn of the adjuster and then it wants 2 threads showing. Set the adjuster so only 1-1/2 threads are showing. Now adjust the pushrod so it has zero play.. That's the length you need. If you were to turn the adjuster another 1/2 turn you'd have the correct preload and the two threads showing on the adjuster.

For a solid cam you'd set the adjuster with two threads showing, the appropriate feeler gauge between the valve and rocker tip and then set the pushrod for zero play.