Set each rifle up for the position and magnification it will be used at the most, if eye relief is picky.
If you get a lot of snap shots and you run the optic mostly on low power, then set up the rifle so when you shoulder it standing (or however), it comes up as quickly and easily to a good sight picture as possible.
I set most of my rifles up either sitting or kneeling and square to the rifle. As I spend most of my time shooting positionally for practice or at matches.
When prone, the rifle isn’t exactly set up perfect, but prone is when I have time to move my head or whatever I need to make it work.
For what it’s worth, without a fully adjustable stock such as the AX that can be adjusted on the fly, most rifles will never be perfect for all positions......prone, unsupported, or positionally. So you pick where you will be shooting the most and/or the one where you have the least amount of time to adjust to, and set the rifle up for that.