Travel to Amsterdam - How can I manage the crowds?

I'm planning a trip to visit Amsterdam before the coffeeshop ban (possibly) goes into effect in 2012. I'm aiming for late November so I can attend the Cannabis Cup as a judge. There are a few coffeeshops I want to visit too, but would rather go while I can get in, feel comfortable, not rush, and enjoy my time - essentially not be another part of the tourist pack. I've been looking at Barney's and Amnesia, but heard the latter can be a bit "uppity" about serving foreigners. If anyone has any recommendations, I would love to hear them, also is the city busier before or after the Cup? I think I'd like to have a few days with less people so I can actually hit those places! Thanks!