Pin distance can be relevant if you know how you want to set the ball up - but it depends on your PAP. In fact, the pin distance will determine where the heavy spot of the ball will be located, relative to the pin, and this has impact on the static weight distribution. While the effect of static weights on ball reaction is minor, it is important for the legal weights. So, if you know that you want a flippy length layout, a longer pin distance will be a good choice, increasing finger weight for length and keeping the CG in the palm area while you place the pin above the fingers. The same drilling with a short pin distance would force the ball driller to put the pin under the fingers - a much more rolly layout.
On the other side, a short pin distance can be helpful for early roll layouts, for heavy oil balls for example. Pin under fingers, CG swung out to the PAP plus a weight hole - a long pin distance will make this difficult.
If you take a look at Brunswick's drilling sheets (sym. cores), there are pin distance recommendations, and they serve thsis etuppurpose.
While a good ball driller can compensate a bit for the pin distance, selecting a ball that has a good basis for what you want it to do is IMHO a smart move, instead of buying anything from the rack and letting the ball driller do whatever he/she can make out of the orb.
--------------------
DizzyFugu - Reporting from Germany
Confused by bowling?
Check out BR.com's vault of wisdom: the unofficial FAQ section