Is this a CIS or CIS-E car? Stock VW stuff goes lean at high rpm. Adding a potentiometer in line with the coolant temp sensor will let you add fuel easily. Set it up with a bypass switch, manual or a relay triggered by full throttle switch, so it is not overly rich at idle/paddock speed.

No timing advance is fine. That means the knock sensor is not meessing with your timing. Set it at 31-33 and leave it there.