Rande, Ron, & Larry - thanks for your kind words, I really appreciate feedback from the board.
Rande - You've posed the same question I've asked for many years, and the answer finally dawned on me as a result of reading Wolf Marshall's articles:
I want to sound as authentic as possible when playing a Merle song, so I need to use Merle's right hand technique when playing his songs. If I use thumb/two or thumb/three-finger to pick, then I'll sound like Chet imitating Merle. There's a slight millisecond difference between the two right hand techniques, but it's enough to alter the sound, and the Travis Groove - that's why Eddie Pennington insists on using just a thumb and one finger approach.
If you were to watch my right hand during a gig, it would change depending on the song and style I'm playing. I use the Chet right hand for his songs, Merle's for his, and Jerry's for his. When I play jazz, I'll use either a thumb/three-finger approach like Ted Greene, or even a straight pick. What I'm focused on is the end result-the sound that I hear in my head. Working on fingering exercises, right hand exercises, and so on, just gives me the ability to mimic any style I want to, within reason.
I also follow Bruce Lee's approach: he advised that when studying somebody's technique, take what is useful to you and discard the rest. What I'm saying is this: take the time to learn some fingering and right hand exercises, and figure out what is useful to you with respect to your musical goals. I guarantee it's going to be different from what I do, or anyone else for that matter. Bruce Keener works from a Christopher Parkening book, while I work from both Carcassi and George Van Eps books. It depends on what you respond to musically.
I hope this helps answer your question, and I haven't rambled on like a politician-
Randy