The adjustment can be made using either the different thickness ball socket (on the end of the valve stem) OR by using the different thrust element. Since you are at the thinnest ball socket (3.0mm) and are still too thick, you obviously need a thinner thrust element. Going by memory, there are marks on the thrust element to help identify their thickness. The thinnest one has one "dot" in the middle of it on top, you can see it by looking at the top of the rocker arm, the top of the thrust element is exposed. This is the most common when the engine leaves the factory. Many people assume the "dot" is an oil hole, it is not, it's an ID mark. I believe the next thickness up has 2 ID dots, and the thickest one has 3 dots. If you at the thinnest thrust element and the thinnest ball socket, you may need to either have the valve job done over using new valve seats installed, or replace the head.