The front is definetly the place for airtime, especially if its a full train in 90 degree heat. Theres one, actually two advantages in the back seat. On the first drop, the back seat gets a sort of "whipping" motion similar to AC or RB. This produces spectactular free-fall airtime (if you're not stapled in). After the hammerhead, on the fourth hill, you get another batch of incredible free fall airtime as you crest the hill. I think its because this hill is smaller, and has more upward force as the downward curve increases.
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*My Personal Top 5*
1)-Nitro, 2)-S:ROS(sfne), 3)-Kraken, 4)-Alpengeist, 5)-Incredible Hulk