Whatever makes the most sense to you
I used to sight all my rifles in 1" high at 100 yards for the 300 yard no holdover shot. Most of my hunting is in timber in the Upper Peninsula and I have since re-thought my theory. While I do walk across a farm field that could present itself with a very long shot, I probably would not take it as I don't practice that far and wouldn't feel right lobbing one out there. However, being a handloader and knowing my exact velocity and trajectory, I know that if I can see horns with my naked eye that I can hit it without any holdover as none of my loads drop more than a boiler room hit on an average size deer anyway. If you sight dead on at 100, then all of the ballistics come into play easier. If you know that your load drops 3.7 inches at 200 yards and 12 at 300, then you don't have to "figure" that extra inch or 1.5 inches into your computation. If your gun is 1.5 high at 100, and your drop is 12 at 300, how high should you aim to hit dead center? The correct answer is 10.5, but the question is, how high is 10.5 on a deer? The average deer in my neck of the woods is about 24 inches top of back to bottom of chest, so I would hold just below the back at 300. However, knowing that my drop is 12 I would know that I instantly hold the horizontal crosshairs on the top of back and I'm in the boiler room.
A laser range finder will let me know exactly the range, but once you put the scope up for a long shot, you are probably aiming at a deer and not a spot on a deer as your crosshairs are probably just as big as the deer is anyway. YMMV but that is my theory.