Thank you for the video postings first of all as they were most entertaining, and interesting. I am by no means an "accomplished", or even very good classical guitar player, but my first instructor in classical guitar was an old, and I mean old family friend who loved Carlevaro and spoke of his methods often.
I am not sure if in his opinion of nails vs no nails he was also referring to Carlevaro or not as he did not qualify the remark as belonging to that school of thought, however as he put it and as close as I can recall, "In the striking of the strings on a guitar, there is not as much difference as is often argued between playing with nails or without. The actual striking of a skilled one who plays with nails involves not only the nail but also that little fleshy part of the finger. By a very small adjustment, one way or the other, the skillful player can change tone, and more, so really it is a question when playing of not nails vs no nails, but one of how much or how little of either."
As I have said above, I have much to learn myself, but in playing around with this idea and experimenting on even a very simple piece of music, I have to agree with this view, that the debate is a moot one, which each player unique onto themselves. In the end, of all the various musical pieces I have listened to over the years, I never paid much attention to or cared about nails or no nails when the player was obviously a skilled player and only took note when a player claimed mastery but exhibited a great deal of extraneous "noise" such as string scratching and acted as if it were a normal part of the musical piece. In the end what is important is the perfection and beauty of the music.