You want a "heavy oil, flood capable ball", but are getting away from Track, because they are too strong?
You "need to go back to symmetrical stuff" but are choosing a Hawg Zilla, which is asymmetrical?
If you like your brother's reaction, drill and cover prep it like his. 1/4" difference in your vertical PAP measurement will have very little difference in your reactions. However, stacked leverage is not a flip drilling. If his is "flipping", what he is bowling on isn't heavy oil to a flood. Make sure you take this into consideration if you are actually intending for yours to be useful on such a condition. If you do, start with the cover at around 600 grit wet sanded and go from there. It will roll early and be very smooth on the back and will roll out if thrown on medium oil. If it does, gradually increase the grit of paper used (1000, 1500, 2000) or add a small amount of polish.
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Ron Clifton's Bowling Tip Archive