The main reason I want to go to one pin is to clarify my sight picture. I shot a bit tonight and learned some things. I know a zero'd pin at 20 yards with my current setup will shoot to point of aim in to 13 yards and out to 28. At 5-10 yards, it's 1.5" high. At 30 yards, it is 1" low. At 35, it's 3" low. At 40 yards, it's 6.5"-7" low.
This is also why I can't do the 2 pin set up of 20 and 40 and splitting the difference. If I split the difference for 30 yards, it would shoot about 3" high due to the smaller drop from 20 to 30 than from 30 to 40.