So I finally managed to finish this triangular scarf. It took far longer than it should have, but not because of the fine yarn or the 2mm needles. The reason it took so long is that I left it lying around untouched for about a month with only a centimetre and a half of the border left to knit (because the fact that I'd have to improvise to finish with a full pattern repeat rather than half a one psyched me out) and then dithered for another week before plucking up the courage to graft the ends of the edging together (because the fact that the end had more stitches than the beginning psyched me out).
After all that angsting I grabbed the piece a couple of evenings ago and just did the thing. Picked up two stitches instead of one from the end row pretty much at random, in two places, to make the stitch counts even out. And the result is such that even though I know where the graft is, I can't for the life of me see it.
So much for being scared of one's knitting. :)
Note for future reference: The edging is "Cyprus" from Victorian Lace Today, but I stumbled across a different way of attaching it that doesn't leave a horrid little bumpy ridge on the wrong side of the piece. What I did was to slip the last stitch with yarn in front on each wrong side row, then knit that stitch together with a stitch from the edge of the centre panel at the start of the right side row. This is pretty much the exact reverse of what the book says to do when attaching the edging, but it makes for a beautifully smooth join that looks just as good on the wrong side as on the right side.