Re Joseph Spence,

If thats how he wants his guitar to sound that's up to him. He's the one that's playing it.

Standar guitar tuning is a compromise at best.

You can tune the open strings perfectly but the intonation will vary from key to key.

I think I've heard standard tuning described as 'tempered' which probably means making the best of a bad job.

String height from the bridge, and the force you use to hit or fret the string will also make a big difference.

The 'Guitar Book' by Tom Wheeler explained this in great detail and is well worth a read if you can get hold of it.

While we're at it, Indian musicians use a 100 cent scale per octave instead of our miserable eight note job.(Phew!)

Ry Cooder's advice on slide playing was to "move up and down the neck until you can stand it."

Apologies to any real musicians or fruit bats.....