Os 37 with century muffler in hawk pro

[Dilbeck]

Anyone have some needle setting that work best for this setup? The stock muffler was factory setting on low needle and one turn on high, Ran perfect. Now it runs lean so went 1 and a half turns seems a little lean so went 2 turns and think its better but not so sure cant seem to get it just right with this muffler. Depending on how cold it is outside it seems im going back an forth from 1-1/4 to 1-1/2 to 2 turns out. Any help from this engine would be great.