This topic is visited on here SO often. I usually see people posting that if you have an adjustable rib and and adjustable comb, the comb changes POI. And I disagree.
Adjust the rib (if possible) for the POI that you want. Many even have marks or tell in the owners manual what rib setting with give what POI (with a margin of error). Then adjust the comb so that the sight picture and rib/sight alignment are what you want to see.
Personally I like my gun to shoot about 80/20. So I set the rib, shoot the pattern board with my gun in a solid rest/gun-vise and the beads lined up on the pattern board so that the beads are "snowmanned". My head never even touches the comb for this. I treat it like I am sighting in a benchrest rifle. If the pattern/POI is not 80/20 I adjust the rib up or down to get it there, and repeat as necessary.
Once the POI is set with the rib and you are happy with it, adjust the comb so that the gin fits you and you get the rib/bead sight picture you want. I always tell students and others I am helping to mount the gun with their eyes closed. adjust their head, shoulder, EVERYTHING about their gun mount with eyes closed so that they get the gun perfectly where they want it and it feels best. THEN open their eyes. If they are not lined up on the rib and beads like they want, adjust the comb a little and try again... with eyes closed to start.
If you do it with your eyes open when you first start, you will just naturally put your head down so you are correctly on the rib, and may not be in your natural/neutral mount position.
Just my thoughts, not sure they are even worth a penny, but... lol
As an added thought... Once everything is set up like this (POI what you want, gun mount comfortable and neutral, rib/bead alignment what you want) you can just about forget about the beads and rib then. Just 100% mount the gun the same every time and follow the target.