Hey Jack! I'm really happy you like my material

. To answer your questions:
1. The move can be performed from
ANY angle.
2. It's not easy nor that hard. After you practice it a couple of times and get the knack of it, it'll become easier. Also,it is necessary that you know how to do a "Off the
Thumb Spring" ,but Andrei will cover that as well.Then you just have to work the pattern and presentation.
You have to remember that is not of those sleights that once you know the secret you can immediately do it. This one does require serious practice.
Cris.