I want to clarify the pin length and what differences it makes. The longer pin vs a shorter pin?
Which pin length are you referring too?
The Pin to PAP measurement? or Pin to CG measurement?
Pin to CG measurement
Different pin lengths here can make it easier to use different layouts. a 3"-4" pin length is a standard range and it will let you use most layouts.
Too Short/Long distances can limit layout options. The length is marked on the box or you can measure it with a flex tape or quarter scale.
The Pin to PAP measurement
At the simple level the Pin to PAP measurement will adjust how much the ball flares.
On a symmetrical ball 3 3/8" is the strongest point.
On a asymmetrical ball the farther from PAP the more it will flare.
Closer to 6 1/4" produces more forward roll, closer to 2 3/4" produces more side roll.
To measure it you would need to know where your PAP is.