Just as you said, full rollers track between the thumb and finger holes. For a righty, I believe the track goes from the left of the middle finger to the right of the thumb hole. Even for a semi-roller (most people nowadays), the track should not clip the holes, though it does for some (me, with certain balls).
As I understand it, full rolling happens when you rotate your hand from the outside of the ball to the inside or behind it at release. The FR I know does that. Semi-rollers either stay behind and rotate to the outside (see Mika and many others) or rotate from the inside out (PDW, PA, Amleto).
SH