I always rhink debates about size of club to be, quite frankly, pathetic. It doesn't matter and neither can anyone agree on the criteria and the weighting given to the various factors. You usually find that supporters select the criteria that favours the club they support.
As for numbers of fans, I have lived in London for 12 years, and in my experience Arsenal, quite comfortably have the biggest fanbase.
I am sure Spurs have a sizeable fanbase. However, I don't believe they have a huge waiting list. If they did, surely they wouldn't get such low attendances in cup games. A waiting list means nothing unless those who are on it are willing to stump the cash when they are told they can have a seat.