First of all, thanks for all the effort to research and model this!
A friend of mine did some modeling as well, and came to the conclusion that there should be a treble increase, rather than the perceived decrease:
Even though the exact values differ from your (probably more correct) model, the effect is clear.
So, what could we really conclude from all this? That our models are too simplistic? It seems like they contradict your empirical tests? One indication of the complexity is the fact that in your real recording example, the 12th and 13th component is really louder in the rolled-off case, right?
Most people know him from the films, but he is one of the greatest songwriters for the guitar in history! Incredibly talented, funny and musical. He saw himself more as a "guitar writer" than "guitar player".. he said.. "I wrote it, now YOU play it!" :) But man,.. could he play... amazing!
Congrats! That's a nice guitar. In the future, just go out and play them. If you want to know the difference between two of these track them down at a guitar shop and play them. Nothing is better than your own hear. :)
@emilernebro I am working on Banjo Rolls. Just worked my way through the Cycle Solo and can more or less keep up at 1/2 speed. I posted a question regarding technique on a particular passage in the piece in another post. Cheers.
I have the neck on the guitars very straight, and I give it to my luthier for saddle/nut adjustments. Usually he does a fret job on it to make it not buzz too much even though the neck is straight.
I have the action set low, and I use D'Addario strings, phosphor bronze 12-53 (although I use a 14 on my high E string to get a bigger tone on the high E string. I rarely bend more than a whole step on that string anyways, so I can have a thicker string there.. Learned that from Joe Robinson :) )
Let me know if you have any other questions!
Kind regards/Emil from ProGuitar.com