I have my Sterling jp70 tuned to drop Ab and the saddle on the trem is tightened all the way. It will not intonate properly. It's still sharp at the 12th fret. I have a .64 for my lowest string. Is this an issue I can even correct? So far I've thought about a gotoh replacement bridge or an esp/ltd compensated nut, but the compensated nuts are 48mm and the jp70s nut is 50mm. Help me SSO!