If you know the hotel were they are seated, than that's the best way in my opinion.
I did it in Amsterdam this year and it worked.
I saw him in 2001 at my first concert, after the concert, but then he was just waving.
In 2005 he signed some stuff for other fans at the artist entrance.
RAH gigs seem pretty impossible to me, because of different exits and MK seems really good at avoiding then
In my opinion, defenitly before the concert.
At the hotel or the gigs entrance