I just post my personal experience:
(Excuse me in first, for my worst English)
I spent a lot of money, jumps and time for trying to HD on my own and then I realized that is better know the tecnique in first.
I started to make some jumps trained by Olav and his school and I understud the right way to stay HD.
Last saturday I made my very fist jump (from exit to open) all in HD and I'm really really satisfied!!!
See yaa!
Theo