I'm going to guess that 1500 will turn up, as there are obviously a lot more Arsenal fans around than there are of Millwall, but not as many as Charlton seeing as they are the local side. Hopefully I'm wrong, and 2000+ attend the game.
If we get over 5,000 for those three friendlies then we have got what we wanted finacially THEN Jamie can use the next few friedlies to get the team in real shape getting prepared for the Hampton game