I bet he has enough cover ups sat on the shelves unplayed that mean he could stop collecting now and still be the No1 DJ for years and years.
Buying tips would be use loads of ebay names, buy anything thats round and has a big hole in it and build up a huge network of contacts.
easy
I wonder if he actually enjoys this god like status he now has. My guess is he would be just has happy buying his soul records and keeping out the spotlight.