kodiakbear7070 you need to run 2 .020 shims for a total of .040 of head shims for 30% on the Axe Rossi mamba SG X 1. But you need to Check and make sure you head button has a 3 stamped on top of it. Axe Rossi had some stamped with a 2 for 20% not sure way they did that but they did.