Carolyn left a detailed comment about working with the GST. I thought more people would find it here:
The main feature of the thread that I had to learn to deal with is similar to what the stitchers have noted: it is raspy when rubbed against other threads. This means that when tensioning, I had to be very careful to note if the GST got caught anywhere and had to fuss with it a bit more than some other threads. The positive side was that once in place, it did not move much because of the wire structure.
Another tensioning problem was that the silk stretched a bit more than the metal, so if pulling too hard the wire would break leaving an area of bare filament silk that “puffed” a bit if not twisted. These areas were not very noticable if in whole stitch cloth, but showed up more in half stitch or filling areas. Once I got used to it, though, I could avoid over-pulling and my rate of metal-popping went way down.
If the GST rubbed too much on the edge of a bobbin or hairclip (I used the same kind of small hair clip to hold the thread on the bobbin as is used for the metal threads, shown on an earlier blog entry) the wire would break, so I also learned to make sure I moved the rubbing spot often. Kind of like avoiding nerve wear in carpel tunnel syndrome!
I’ve now finished the Torchon square with the GST so can also comment on tying off with it. I used magic threads at the start, so just had to pull the GST through the loops. It was raspy, and in one case my magic thread broke because it was so much thinner and weaker. Overall, though, it was easy to manage the GST and the knots held well. I used a surgeon’s knot(http://en.wikipedia.org/wiki/Surgeon’s_knot) to make sure the silk held tight. The knot ends could be bent over to a spot on the back and stayed put because of the wire.
And the outcome? The colors are wonderful, the lace has some structure from the wire so I could see using it for flowers, leaves, etc in 3-D work, sort of a middle-ground between silk and actual metal wire. The gold is not obvious but adds another depth of sheen to the silk, and glimmers subtly in certain angles of light. I really like it and plan to use it for more lace pieces.