Really good comments. I started out playing on a Epiphone with a standard setup. I have a step-son who has been playing for close to 30yrs. He has gone through most of all the things mentioned. He has sat down with me on hand positions, thumb position, guitar position, and he has had me play both of his Martin’s.
When I roll my hand more then the palm hits the bottom of the neck and I tend to mute the high “E”. We tried changing the position of my thumb to put more of a arch in my hand. I struggled with it and I have watched the bend of my fingers, making sure that I don’t make them too stiff and am up on the tips like Tony instructs.
Now on to the guitar, I have gone to the Music store, I have looked at the orchestra guitar. I didn’t like the feel of the strings or the sound. I asked them about wider necked guitars and they told me that other than the orchestra model they don’t make wider necks. Well, I searched the internet and I finally found Zager guitars. The necks are wider and the spacing of the strings is wider, and I still have the problem with my fingers. I love the feel of the neck and there is more space between strings but no relief on muting. So, I haven’t really tried the putting the capro to the 5th fret. I guess that is next. 🙂