Well, I'd have to say it depends on who you are racing against. If I'm at the track racing against you, I'd say 1" of toe-in would suit you just fine!!
Seriously, though, I usually set mine for 0-1/16" toe out. That's about the tolerance of my old measurement system, but it seemed to work OK last year.
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Bill
Planet 6 Racing
bill (at) planet6racing (dot) com