Follow the mfgs recommendations. You'll get different centerlines depending on where you measure so just follow the instructions. They might tell you to use an 0.050 lift number, or perhaps they'll tell you to use something else. They should know how they want it installed.

BTW - this question sparked a huge debate on the old SpeedTalk board that went on for months. Mike Jones kept telling everyone to shut up and to just follow the mfg instructions but people kept arguing about where the center line is on a non-symmetrical lobe.