My opinion page addressing inquiries concerning clawhammer technique.
Try slowing any song you want to perfect down to a "crawl". So slow you can hardly play it! Use a metronome if you have one. Work at this tempo, concentrating on timing, tone and note duration (how long a note rings out before you remove your left hand from the string). Spend some time analyzing your right hand technique when you do this.
Once you can play through the song to your satisfaction, increase the speed a little (and I do mean "a little") until all the notes ring clear at the new tempo. Keep this up until you've got the tune where you want it.
I was reading an interview with the great bassist Edgar Meyers and this is the technique he uses. I'm sure Bela Fleck did this as well when preparing for his classical album. Try it, it works!
Thanks... Mike