Bridge/saddle height is set by the neck angle, as they are adjustable and the neck angle isn't (assuming that a neck reset it not being performed). The point is to get enough energy into the top to vibrate it so that it sounds its best. The amount of energy required is set by the top thickness and material (several varieties of spruce, mahogany, maple, and cedar, although there are others), and the top bracing, as well as string tension (either variations in the strings, or string gauge). All of that is designed in. and not variable without basically rebuilding the guitar. Guild's production methods, from what I am gathering above, is to sand the bridge height down to match the neck angle. I have seen hand builders do it the other way around: use a standard height bridge, and fit the neck joint so that the neck angle matches the bridge. It is probably more consistent with the way the hand builders do it, but would be too time consuming to do in a volume production environment.
The ideal way would be to actually be able to measure the downward string pressure, but this is not really possible, so we (as in the acoustic guitar world in general) have a couple of ways of getting the required string energy into the top: either bu changing string gauge or string brand (variation between various light gauge strings). or by adjusting the height of the saddle. Lowering a saddle changes the string break angle, which also changes the string energy going into the top. excessively low saddle have a shallow string break angle, and less string energy is put into the top. Excessively tall saddles put too much stress on the front of the bridge, and can cause the front edge of the bridge to split (this can also be caused by a too loose fit of the saddle to the bridge, or even a too tight fit of the saddle to the bridge). Between those two extremes, adjust the saddle height to suit the playability that the player is looking for.
The Frank Ford specifications look right to me. Anything within 1/16" to 3/32" should work fine in just about all guitars. But the real determinant is the neck angle, and that will vary from guitar to guitar (even in the same brand model) and from brand to brand. I wouldn't be concerned with Al's D40 combined saddle/bridge height if the action is OK for him, and there bridge is not showing any signs of cracking. There may be a little bit more neck angle on that particular D40.
Factory saddles are left high intentionally, because you can't stretch a saddle's height, but you can easily shorten it. Factories also ship guitars knowing that most of them will have a setup done prior to delivery, so the saddle height will be set for the player then.
Headstock mass is not really a concern with volume, but is it through that it has a very minor effect on tone, and a more substantial effect on sustain. That is somewhat controversial, but adding some amount of headstock mass (in the form of a capo clipped onto a headstock temporarily) does add to sustain. When a guitar is vibrating, all part of the guitar vibrate to some extent, the top, sides, back, neck, air inside the body, etc., and not all of them vibrate at the same frequency, so the vibrations have an extremely complex interaction.How all of these interactions work with/against each other is what makes the tone of the guitar. Most of the tone and volume of the guitar come from the top; however, the vibrations from the other parts of the guitar colour the tone of the guitar in many ways, although they are minor contributors.
The ideal way would be to actually be able to measure the downward string pressure, but this is not really possible, so we (as in the acoustic guitar world in general) have a couple of ways of getting the required string energy into the top: either bu changing string gauge or string brand (variation between various light gauge strings). or by adjusting the height of the saddle. Lowering a saddle changes the string break angle, which also changes the string energy going into the top. excessively low saddle have a shallow string break angle, and less string energy is put into the top. Excessively tall saddles put too much stress on the front of the bridge, and can cause the front edge of the bridge to split (this can also be caused by a too loose fit of the saddle to the bridge, or even a too tight fit of the saddle to the bridge). Between those two extremes, adjust the saddle height to suit the playability that the player is looking for.
The Frank Ford specifications look right to me. Anything within 1/16" to 3/32" should work fine in just about all guitars. But the real determinant is the neck angle, and that will vary from guitar to guitar (even in the same brand model) and from brand to brand. I wouldn't be concerned with Al's D40 combined saddle/bridge height if the action is OK for him, and there bridge is not showing any signs of cracking. There may be a little bit more neck angle on that particular D40.
Factory saddles are left high intentionally, because you can't stretch a saddle's height, but you can easily shorten it. Factories also ship guitars knowing that most of them will have a setup done prior to delivery, so the saddle height will be set for the player then.
Headstock mass is not really a concern with volume, but is it through that it has a very minor effect on tone, and a more substantial effect on sustain. That is somewhat controversial, but adding some amount of headstock mass (in the form of a capo clipped onto a headstock temporarily) does add to sustain. When a guitar is vibrating, all part of the guitar vibrate to some extent, the top, sides, back, neck, air inside the body, etc., and not all of them vibrate at the same frequency, so the vibrations have an extremely complex interaction.How all of these interactions work with/against each other is what makes the tone of the guitar. Most of the tone and volume of the guitar come from the top; however, the vibrations from the other parts of the guitar colour the tone of the guitar in many ways, although they are minor contributors.
