My arm span is 67.5" so thats 27". I shoot 28" with every bow I ever owned for 3D. Maybe for hunting only I might want my arm bent more but for 3D 28" is perfect.
No way can someone feel that little of a difference. Given a blind test it would be "hope I guess the right one". Anyone that says that I'm sure can shoot 4" groups at 100 yards and uses the same pin for zero to 40 yards with no drop. It's an old tune when you been around archery for a long time.One person noted he could feel .040" off.