I would do everything possible to reduce weight. I wonder if the spring recommendation takes in to account the exhaust rocker’s size and polar moment with the roller and adjuster so far from the fulcrum. Im not saying it won’t work... I honestly don’t know. That being said, if you are using the same spring on the exhaust as you are on the intake, you are either over-springing the intake, or under-springing the exhaust.
If this sounds wrong, let me know your opinions. I don’t have any real life experience with the early hemi, but this is the line of thinking with the one I’m putting together.