When it comes to relievers, I can't see how you think you can reliably estimate W's. You can't do it with great accuracy for starters let alone relievers. Luck is a huge factor. Sure guys like Rincon may get more chances, but hey who is to say the Twins win those games and go ahead while he is still elig for the W? Take 4 or 5 wins away from Rincon last season by removing 4 or 5 hits in the late innings in all liklihood. Things like that are complete luck. Sure you can get lucky and stumble into Koch in his one year or Graves a few years ago. I would not bet a dime on the Ws for relievers. You have to predict 4-5 Ws and anything over that is just gravy IMO, but that is me.
As for Pettitte, no one claimed he is an elite SP. And comparing any SP to the top owner in the league is silly. You compare to the league avg, not the league leader isn pitching or the winner. They could have been very lucky, could have drafted all SP and no hitting, etc. You can't make an argument that the league winner in pitching had a 3.2 ERA and every pitcher worse than that is no good or hurts your chances. That is silly. The overall fantasy league avg for SPs in a 12 team mixed league with 8 or 9 actuve Ps is no where near 3.3.