measuring for pushrods with a hydraulic cam

I take it you are using non adjustable rockers?

If you are, and have a pair of old pushrods, you can make your own checking tool. Cut them in half and thread the center. Twist them until all the lash is gone and add whatever you want preload to be once measured.

Not that tough to do. You need a pretty big micrometer to measure your finished length.

Using adjustable rockers, you likely need a ball cup pushrod checking tool or your can fudge it with a ball/ball checking tool.