I, too, have a fly tying travel kit..but I put all my threads on either the
spools that go with my Norvise automatic bobbin (take up lots less space and
love the bobbin) or wind them on sewing machine bobbins..clear plastic.
These are then used with the mini bobbins and carry such things as Sulky
gold and silver thread, round DMC thread, etc. They hold lots and you can
get a neat bobbin box that is very small, thus taking up lots less space, to
hold them. Check it out..I think you'll like it as well, if not better, than
big old thread tubes. All my woolly nylon, floss, even the odd color of
standard thread goes on these. The bobbin box is either a square one or I
have found, and love, a round one in which the bobbins just pop in and are
held in place by two plastic lips. Go take a look at your favorite sewing
and fabric store. You may want to consider this for the colors and threads
that you don't use as often. Joyce