I'd been experimenting with that Roddick "palm down and forward", broken wrist idea just entering the trophy position in the beginning of Dec.
Immediately, I got more power. And less control.
Kept at it for over 100 serves spread over a week, got more power, more racket head speed on my flat serves. Didn't use it for second serves, because I need to walk before I can run.
Gave it up because in application, the serves didn't go IN often enough to justify a change of motion. It did get more ballspeed.
I play tennis about twice a week, at best.
If I played 6 days a week like I used to, I'd consider that service motion.