Hi Martyn, A 'deliterious effect in the bass', maybe, but there is no bass below the g, at least in Sanz's specified tuning. So, no, Martyn, I did not use modern bass strings. Another important factor is that Sanz does not mention pitch - we have no idea what pitch he used. Some argue that Roman pitch was around 392, others say it was nearer 460. We don't know his string length. We don't know if he used different sizes and pitches of guitars. We cannot assume that all his works are for the same instrument. All we have to go on is the music, and what we can read into it. The recording with the high octave g was done 5 years or so ago on an original anonimous guitar from mid-17thC France (it is thought) with a short string length (can't recall the exact length). It was entirely strung in gut, tuned to around 392, no bourdons, therefore no bass. The high g did not break, and although unplayed is still, I believe, on the instrument. It is housed in the collection of Edinburgh University.
So, at a lower pitch and no bass register, it might well be possible to have a high octave on the third. How long it would last when regularly played has not been tested by me. However, I don't want to be seen to be advocating the tuning as I am not one who thinks that Sanz only makes sense with it. I repeat that I am happy playing works which leap up and down octaves, and see it as part of the charm and uniqueness of the instrument. But it is worth mentioning that a) the tuning with a high ''g'' is possible (nominal g, of course), and b) that the particular piece 'fuga 1' seems to be 'happiest' (if you will allow me that term) with this tuning. But mainly my stance is that 'I don't know'. Rob -- To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html