Well I say 2 slams and 15 weeks at #1 is better than 1 slam and 60 weeks at #1.
...But 1 fluke GS < 10 weeks at #1. It just depends on how you look at it. IMO you have to be more well-rounded for #1 where as you have to play 2 good fluke weeks for a GS. There are far more fluke GS champs then there are fluke #1's.