Help! There are a million strings for mandolins, nickel or phosphor bronze, different diameters, some are wound and or coated, some say they are high tech and last a zillion times longer - the only thing I know is I need loop end not ball end, and like lighter rather than heavier. Can anyone give me the idiot's guide to the options to help me choose - and maybe a decent source for good value quality strings for general purpose use? Thanks CHRIS