[JP Noonan]

I can't really explain the relationship between the rocker and valve tip. Look at some VW books like "How To Hot Rod A VW Engine" and Tom WIlson's "How to rebuild an air cooled VW engine". I know they sell shims that go between the head and the rocker shafts. BTW why are you replacing the rods? If you have a stock cam and stock length push rods then there should be no reason to adjust geometry. It is a good idea though, because things like the cylinder head shims and head gaskets can affect the valve train geometry.