As long as THS is consistent, there's not really a need for more than 2 balls. I don't use a plastic, so generally its the original inferno and fire quantum.. Unfortunately the lane man at the local center likes to have fun sometimes and use the old lane machine, which is a flood from gutter to gutter. So anything short of sand paper won't wrinkle. It's for this reason I usually bring at least 3 balls, knowing full well i won't touch anything stronger than the Inferno but one night a week.
Fortunately for me, there's a serious summer league that pays $1k a man for first place, so i can't afford to be unprepared for the lane mans tricks.
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When all else fails, become a lefty