The LX flight usually parks at D4 or thereabouts. On coming up the airbridge the main immigration is more or less directly in front of you. Turn left and the CIP immigration is about 50m further down.

Last time I flew in on LX was in June and the main immigration was packed out but there was nobody at the fast track. From plane to baggage belt in less than 5 minutes. Shame that I had to wait at the baggage belt for ages as LX had managed to leave my suitcase on the tarmac at AMS rather than putting it on the ZRH flight as they were supposed to.