no 12.5 is the best power eithr turbo and n/a

there is no frmula for that you should give you engine what he asks for beginig start rich and the lean it till the knok's but ther are more parameters to play with like ignition but all depends on your set up C.R 8v or 16v ect.....

my strong advice BE carful and use an egt gauge to!!! sart mapping from ninimal boost to max with steps no more tan 4-5 psi each time