I use the 3" high at 100 yards as well. Having used it for over 40 years, it works for me. It did take a while for me to discipline myself to hold for the center of the chest for the forst shot. I only use 180 gr. bullets in the 06 anymore, but zero is about 225 yards. Holding for the center, if the deer is within that 225 yards, he's dead, hot liver in the pan. If I see the bullet hit under him, usually a top of the back hold will drop it in farther out than I like to shoot.
Now if I'm hunting in an area where I know all shots will be short range deals, then I sight in from dead on to one inch high at 100 yards.
FWIW, with ther exception of two deer, all my game has been killed at 200 yards or less, mostly less. My last two deer were both taken under 35 yards, both Mule Deer in the open.
Works for me.
Paul B.