I couldn't find this specific topic covered.

If you choose to mention brand names, that's okay, but I'm not here to ask what kind of mic I should buy.

1-What does one typically use an LDC for? What about an SDC? And why?

Hi,

My next recording will be ethno-acoustic band. Except upright bass and (maybe) one violin, all instruments are (steel strings) with strong on upper mid/high freq. and lot of hard alternate picking. Comparable in some way with mandolins.