Wow ! What a wealth of info. Thanks, guest. Chime in anytime.

I'm well aware that new strings sound different, and that once I put on a new set of strings I theoretically should know what the guages are. It's just that with about 10 instruments sitting around, including autoharp, mando, banjo, several guitars, etc., one can lose track of what was placed on what, with what effect ! And yes, different manufacturers certainly do make the "same" guages (light, medium, heavy) in way different sizes !

I shall haunt the pawn shops for a decent used micrometer, and in the meantime look for a handy round,slotted wire guage.

I'm surprised some enterprising acoutrement supplier, like Dunlop or Shubb, etc. doesn't make such a handy dandy tool to suck the money out of all us gadgeteers.