Another vote for 60 minutes.
I think this is a far better idea than blocking it 2-5 minutes in, for two main reasons:
1) I know that if I go to a movie site, and that shit pops up anywheres close to the start of the movie, I'm gone. I'm not going to spend 5 minutes filling out cpa offers when I can just as quickly find another site and be back to the same spot in the same amount of time.
2) As mentioned above, 60 minutes in is when the climax of most movies begin. Not only this, but it's all about the invested time. If someone is 60 minutes in to a movie on a site, they are probably going to take the 5 minutes to fill out the offer. For one, a lot of people stream movies QUITE slow. Chances are, if they are 60 minutes in, their movie is already done streaming. These people aren't going to want to go to another site and have to wait to have that last 40 minutes or whatever streamed (some sites don't even let you jump ahead in a movie). Secondly, they have already received something. They have watched MOST of a movie for FREE. It's all about reciprocity so play with their emotions. You have given them something, so may feel the need to give you something back.
This is all just speculation of course - the only way to know for sure, as someone mentioned, is to do a split-test.
Best of luck OP, and way to go against the norm - thats how the real money is made (perhaps it may not this time, but eventually innovation pays off).