I generally observe two types of “bullet spin” from pitchers:
a) Small Dot
this is where the “narrows” of the seams are facing the batter.
Produces a very well defined small “dot” axis that the ball is rotating around
b) Big Dot
This spin is more curveball-ish. the part of the ball facing the batter is the largest smooth area of the ball. This produces a large “dot” axis that the ball is rotating around
Most of the NCAA “riseball” pitchers (like Garcia) throw a “Big Dot” and not a “Small Dot”. (And a few Unicorns throw true backspinning riseball...)
My own observations are that a Big Dot will stay on plane better, and have more true riesball qualities than a Small Dot. Small Dots generally get hammered...
for anyone trying to figure this out, i suggest making a bullseye ball like this one... it outlines the seam for the catcher to see and the backside bullseye is offset 1 inch from the opposing seam that the pitcher can see...
if i'm understanding what corlay is saying, this ball will show it... in slow pitch it seems it's best to have a perfect spin through the center of the smooth spot... but perhaps in fast pitch it's best to have a little wobble in the spin so it isn't going exactly through the middle of the smooth spot... that would make a larger rough side with the seam but smaller smooth side... hopefully these pics can explain it better... ?
this last picture shows the orientation i try to get in slow pitch... however, this is on the downward arc which fast pitch doesn't need to deal with... the orientation you'll want will be slightly higher than this... however, i posted this pic more to show how i want to get my spin directly through the center of the smooth spot because i'm dealing with speeds around 25 mph... at faster speeds you may want the spin slightly offset so the seam makes more turbulence... at least that's what i think corlay is referring too in order to get more movement... anyway... as a slow pitch pitcher... i'm just listening and trying to figure this out too... i know nothing of fastpitch...