My advice is to get to the Kwaremont and stay put. You have TVs, beers, frites and the races passing four times, plus the best race-side atmosphere.
If you think you can move about between spots, be prepared for a difficult time, especially if you have a bike. It gets so busy that at times it's like a shoulder-to-shoulder gathering with no realistic room for a bike. I think you risk getting caught and missing what you came for in trying to get to see extra passes of the race.