I'd say it depends. On a house shot, hooking the ball to your spares is quite effective, as the wall helps the ball find it's way to the other side of the headpin, but, on more difficult shots, hooking the ball is actually to your disadvantage.
Personally, I use both. On my normal walled up shot, hooking the lane for the 7 pin is easy, but on difficult flat shots, straight at 'em is definately the more guranteed method.
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The THING!