Others are going to disagree here, but that's the great thing about this place; you get lot's of different opinions.
I give my new snakes a week to settle, then the first feed. Two days after the first feed, I begin introducing myself with short handling sessions, like 5 min or so every other day unless it is a feed day. I don't handle BPs on feed days.
As they get used to the whole routine I lengthen the handling sessions, always watching for the snakes reaction. If they seem in the least stressed, they go back to their enclosure.
I now have a 7 month old BEL that can be out for a good half hour or so. We watch TV with her. I also have a 1.5 year old male who gets pissy after 10 min. They are all different.
As for the strike pose, here's a video that you can watch. I know it's about boas, but he covers BPs as well, and its the same method.
https://www.youtube.com/watch?v=AlTqqsDadQg