In article ,
Larry L writes
) How the hell do you tell, a year or more later, looking into your boxes
which flies are tungsten, which regular bead

Finish the head off in a different coloured thread.

QED

I f you just want your nymph to sink why not flatten some fine lead wire
to make a thin ribbon, and wrap that under the regular tying. Use a
different coloured thread from your non weighted nymphs for easy
identification.
--
Bill Grey