I usually look at a starting pitchers ratings in this order, VsR, Control, P1, P2, VsL, P3-P5.
VsR and control usually need to be over 70 preferably 75 and for an ace they need to be over 80. If P1 and P2 are over 80, bonus. I find left handed starters don’t do as well as righties. As long as VsL is over 50 I don’t really care, if it’s over 60 even better. P3-P5 I honestly don’t look at that much. GB/FB and velocity are pretty much useless in Starters for me.