Luke
if your blowing black smoke at 3k rpm @3/4 throttle with 10-11 psi of boost your waste gate is opening at 10-11 psi, fuel boost and power are pouring out the exhaust. Tighten the waste gate down one turn. Go for ride see what happens, check your boost, power, and smoke. If boost is too high back off the throttle and turn the waste gate back a half turn. Your probably going to need 2 or 3 turns.