I am putting this in Miscellaneous because this is not about how to drill a ball. This concerns the number of requests I have seen over the past 6 months or so in just about every forum.
{rant mode on}
To my mind, even though drillings seem to have more of an effect than they used to have,
UNLESS
1. you are averaging no lower than about 220 in every league AND every tournament you enter,
OR
2. you want to learn about drillings to become a driller (in which case ballreviews is not the place to ask; go to the IBPSIA website),
OR
3. you know for a fact that your driller is an absolute moron and he will drill the ball the way you ask (in which case, you should probably find a new driller),
OR
4. You have a ton of money and loads of time to waste playing with new balls and new drillings,
THEN
A. stop worrying about how to drill your new toy,
B. let your driller worry about it or just drill everything one way, (label or use just one drilling. (NOTE: I didn't say, "label leverage".)
C. buy 3-5 BALLS (for example: a spare ball, a pearl resin, a solid resin or a sanded particle pearl, and a solid particle),
D, go practice, get a coach and bowl, bowl, bowl in every league, every tournament and every house within an hours drive of you.
When you average 220 everywhere, then worry about how to finesse the lane condition with specific purpose balls. Heck, I'd bet 95% of those who do average 220 or better do not have a clue about drillings and COULD CARE LESS HOW THEIR BALLS ARE DRILLED.
In other words, if you really want to learn to bowland to score well, get your priorities in order. First things first.
If you want to play games, fine.
{rant mode off}
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"...for advice is a dangerous gift, even from the wise to the wise...."
J. R. R. Tolkien