Regarding this issue, there is actually quite a bit of debate on this subject.
Brunswick claims weightholes on PAP reduce flare and weightholes past the pap increase flare.
Lane#1 on the other hand has done experiments that in my mind verify that weightholes increase or decrease reaction but do not increase flare.
Experiment is drill a pin on pap ball. Drill weighthole on PAP.
Very little flare or reaction. Now on same ball plug weighthole and drill a weighthole 9 inches from the grip center in a 3:30 direction. NO increase in flare but a big increase in reaction. Note side weight reduced and top weight increased.
I have found big differences in reactions by weighthole placements. But of course due to my medium revs, side release and softer speed I magnify all ball reactions a lot.
3 types of basic weightholes in my mind.
1. on pap, adds stability and midlane reduces backend
2. Way past pap and on southern hemisphere of the ball(takes out bottom weight and adds top weight reduces midlane) and adds backend.
3. On pap but drilled with 1 inch lateral out pitch (points weighthole towards bottom of ball and for many bowlers(pap near 5 inches adds top weight), and again increases backend reaction. I've been placing these in a couple of balls lately and really liking the results. Actually have only been pitching 1/2 inch south(lateral out, increased midlane and still a moderately strong backend reaction.
3 variants
1. Rev leverage hole. Hole placed way down VAL(cg is also down below grip center and somewhere near thumb). This hole really assists the ball in revving early in high volume head oil situations. (see Ebonite drill sheets).
2. Very large diamater weightholes, (1 1/8 to 1 1/4) these weightholes do seem to add some overall flare to the ball to my eye if off pap(no experiments done).
3. Weightholes inside of pap closer to grip center.
These take out mostly top weight and REALLY reduce reaction at the backend.
This is all I know. Almost.
REgards,
Luckylefty
PS I have drilled many balls over the past year with weightholes 7 inches from grip center and 9 inches from grip center, in general not a good fit for me!
But above pap drilling(straight in)(world team challenge or tour type shot), or pap with lateral out(more reaction), or down the VAL(early reaction) or large holes all work for me.