I've been using DeanMarkley Acoustic Med.Lite for the last couple of years (012,015,025w,034w,044w,054w) mostly because they had gauging that suited my box and style. I tested various combinations from 011-046w to 012-050w to 13-58w before settling on this gauging.

They get changed when I notice that they're getting too stiff (from work hardening) to bend the pitch easily by pressing harder behind the fret, or when they loose too many of the bright harmonic overtones. The slightly heavier wound strings keep fret buzz a deliberate effect with the medium-low action I prefer for finger-picking and occasional strumming.

As much as I love playing the old dreadnaught Martin and Gibson boxes, the custom Takamine I'm playing these days (basically a classical cutaway with steel strings) seems to have fewer problems with feedback or deadness at various pitches. I'd attribute that more to proper combination of bracing pattern, soundbox geometry and string gauging than to particular instrument manufacturers.

As far as the phospor-bronze vs. silver plate vs. blue steel vs. whatever ... the winding adds mass and diameter to the string. From the standpoint of vibration analysis, thinner cores will sound brighter, and winding material's most important property is its density. Almost everything else is marketing hoorah.

(For classical or flamenco guitar I've used nothing but Savarez Blue card. Their nylon formulation seems to have higher elastic modulus than most of the others.)

ps: Mudjack, do you have an address for the Euphonon String Co? That's pretty good pricing!

~S~