There are no industry standards the cam companies are trying to adhere to, so different brands of parts(retainers & locks) will often yield different installed heights.

I use a Comp 10* steel retainer with std height 10* locks as my normal reference point for height.

I’m working on some 906’s right now. They have oversized valves and will be used with a roller cam that will use springs installed at about 1.900.
For this type of build I always use a spring cup under the spring.

I check to see if any of the spring pads will need to be made deeper to facilitate the desired 1.900” IH.
The cups are .060” thick, so this particular one is just about perfect(no need to go deeper).

The next 3 pics show how non-standard this stuff can be.....