What I do is simply use two pins. I will set one at that same 20 mark like most of you are doing with single pin...and the other is set dead on at the farthest yardage I will shoot a deer at. Which now days would be 35-40 tops. So even though most of my bow kills are 18-21 yards, I have that bottom pin as a safety barrier in case the above scenarios do take place that I have two pins to gap shoot with and know not to raise that bottom pin above the deer's lungs. It keeps me from hoping I remember how far the arrow dropped at 35 yds from a 20 yd center. My pin gap from 20 yard pin to 35 yard pin is .160.
In ASA shoots, it blows my mind to shoot Bow Novice class with guys using 5 and 7 pin setups for that class....30 yard max. My bow is a slower bow...shooting upper 270 fps range. I tried using a 3 pin setup with an 18, 23, and 28 yard pins, and my sight picture was too cluttered due to the pins being so close together. I can't imagine shooting with 5 pins just to get to 30. I'm doing it now with 2 pins...one at 18 and one at 30.