Went down this path 12 years ago. I favored timing at 21 degrees with 39psi and a frack load of meth (two M15 nozzles I believe). I liked timing but others at the time were low teens with bigger turbos. I was on a 0.82 35R. Key for me was a fresh prepped deck with an OEM head gasket, OEM 90 style head bolts over torqued to around 125 ftlbs. Let your driving do the rest.