Average time to get the call from your AD

[LondonGuy86]

Hi Guys, first post here so apologies if the question has been asked before. Yesterday for the very first time I ventured into my local Rolex AD (London Selfridges) to buy a GMT MASTER II, Little did I know that there is the so called waiting list. The AD would not give me a specific time frame, however, he did say that the selection process when the watches become available is completely random and does not depend on previous purchase history. I somehow find this hard go believe, anyway my question is what's the average waiting time for such a watch and are there any tips I can use to expedite the process? Many thanks