Okey, never heard about this "three strike" area. But I found a place where I got a lot of bolts.
That contradicts itself. The place you found is a three bolt area. The 1,2,3 bolts just represent how often lightning strikes.

As for the map, I hope this helps

And here are credits for it (whom I took it from)

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-Final Fantasy X- -Thunder Plains' guide- =
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-By-: = KeRoChAn = kero_hikaru@hotmail.com =
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-Final Version- = Last Updated: 21 July 2002 =
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