I shorted this movie a little while back, when it was up higher. Personally, I looked at the price, and felt it had to open at more than $65M opening weekend, and I didn't think it would do that.
Guessing openers is, of course, just an educated guess at best on how they will open, based on tracking, news, stars, story line, etc.
For me..I read a lot of comics when I was young, but I didn't do much with Thor...so I'm not really THAT interested in seeing it. I think it will do decent numbers, but I just didn't see it opening as high as the price was for the stock.
But what do I know?? I shorted Spiderman 2 when it came out too (and I'm a big fan of the comic) and I lost over $5M on that one... so maybe MY opinion isn't the best to listen to.
The fact that Thor did so well overseas does not mean it will here, each market must stand on it's own... but again, it may do very well here, too. The only way we'll know is when the numbers come out tomorrow, and if you are right, and it does well..you can keep your long, if it doesn't do well and will adjust down, you can always sell it off and short it prior to HSX halting the stock!
Good luck either way!