Well, for the dragons I've never waited over a half hour. The line is always much shorter than other attractions due to its placement in the back of the park. For Hulk, I personally wouldn't wait more than half an hour, but since you've never ridden it and it is a unique experience, I'd suggest no more than an hour. For Spidey, be prepared to wait. I brought a friend with me on my thrid trip and waited happily for about two hours. He decided it was well worth the wait: Spidey is easily the most unique and literally unbelievable around right now.
Jason T.