These are calculations/observations/concrete data from a substantial amount of users; made only on 18/19 year olds with a level 5 trainer:
DV 1.8 weeks
HN 2.3 weeks
IS 4.5 weeks
JS 4.5 weeks
But my personal experience HN abit faster than DV >_> JS seems right, and IS faster when the player is taller. This I observed when I trained a 21 year old 7'2" player, and a 6'3" 18 year old, and a 6'5" 18 year old for nearly whole season. Seems taller you are, IS is faster (the 21 year old 7'2" popped faster and more IS than younger and shorter player). By how much I am not sure.