[JonPR]

Originally Posted by sirwhale

I've often wondered why Bert prefered to play up the neck on the wound strings, it's as if he wanted to avoid using the two unwound strings. It is those two strings that I didn't like and led me, eventually, to the Spanish guitar. I wonder from time to time if Bert had similar ideas; preferring softer sounds.

Maybe you know Jon?

My guess is same as yours: he liked the mellower sound of the same note played on higher strings. (He's on record as saying he didn't like the bright sound of new strings, preferring them after a few gigs when they'd settled down a bit.)
In addition, he would often combine open strings with high frets on the wound strings, to get the "harp guitar" effect, scale runs ringing across one another.
In fact, there's a whole opening section of the book which details some of the typical elements of his style, with examples of each.

One them - illustrating the above idea - is what I call his "high Bm", and I found a great example after the book went to print, in "First Light" a duet with John Renbourn. His riff (almost throughout, behind Renbourn's lead) is this:

-------------0---5--/7--|-----------------------|
---------0--------------|----------------0------|
-------0----------------|--0-----7-----------7--|
-----2------------------|4---------0------------|
------------------------|----7/9-----9----------|
-0----------------------|--------7--------------|
 1   .   2   .   3   .   1   .   2   .   3   .

The Em in the first bar could hardly be simpler, but check how he plays that Bm! (Thumb on 6th, btw) Typical Bert...
https://www.youtube.com/watch?v=YL2BxzwwLps

Originally Posted by sirwhale

And for those bends... I ended up sliding up a fret. Too much for me on steel strings, physically, and pretty hard to bend so far, note wise, on nylon.

Right! On the 1971 original, he was tuned down a half-step, and it actually sounds like a plain 3rd -both of which would make the bends a whole lot easier, of course.
But in a later live version (below - you've probably seen this), he's in EADGBE (capo on 1) and bending a wound 3rd with little effort - although interestingly he avoids doing it on the G chord in the verse, saving it for the D at the end. You also see his choice of the high position for the G chord at the end of the first line (5-5-9-7-x-x), as well as the way he fakes his way through the descending chords after that, because he's playing it way too fast for comfort! (Those cans of beer at his feet may have something to do with that... )
https://www.youtube.com/watch?v=JmVA7BHsF1I
Good shot of the bend at 2:13. Ouch!

FWIW I can do the bends myself, but it's the smooth release of the last one into the descending scale run (alternating with open strings) that's tricky. IOW, once you have the bend under your fingers, there's then more practice to get it smoothly integrated. It's like thinking you've got to the top of the mountain, only to find there's a higher peak further on...