The pin should be 1/2" - 3/4" from the nearest hole. Most manufacturers insist that the warranty is void unless it's a full 1" from the nearest hole.
If you're going to drill it, put it in the middle of one of the finger holes, as a safety precaution.
Many manufacturers' balls could be ok if the pin is partially drilled, but it could crack. Brunswick-made balls, the pin is only a marker in the outer cover. Brunswick STRONGLY recommend a 1" distance or drill the entire pin out.
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"None are so blind as those who will not see."