I've trained my small forwards in their jump shot, and i don't really think its 50-50, i had a level 4 trainer while i was doing this for 3 weeks, for 3 weeks i've trained jump shot for small forwards, it was really wingmen. But i was consitrating on small forwards.
For all 3 weeks at least 2 small forwards improved in jump shot more, and i only had one small forward improve in jump range. I think small forwards improve faster in jump shot than jump range, at least, depending on the level of your trainer and the age and potential of your small forwards. From my experience, small forwards hwo are allstar level or above, improves in jump pretty fast. I just got finished training winmen in jump shot, again mainly small forwarfds, and once again for the 3 consecutive week, a small forward improved in his jump shot, and now its strong.