Most effective combination

Lefty, long arms, throws hard, generates a lot of spin. Pick any four pitches

well, your 2 seam should tail away and down (1), a breaking ball inside and down (2), an off speed (change, etc…) (3) and with changing speeds you want to not only slow down a pitch but also speed one up. the 4 seam fastball has to be there in the arsenal (4). If you are throwing over 85mph it will move too. Keep all pitches with some vertical movement. Remember the bat is long not wide.

what kind of movement should i have on my change up?

it depends on how you throw it… some have tail others cut…

i know pronating gets tail, and i know there’s a million different change up grips, but what grip will go best with the arm action?