Lace, but which?

After receiving my birthday gifts yesterday I have spent a large amount of time reading "Sweater design in plain English" and "A gathering of lace". I like both, but since I already have a cardigan in progress and a sweater in planning stage for me, I put that book aside. It's great though and well written. Something I can't say about "spinning designer yarns". I've only skipped through it and read some passages, but found it dull. Nice pics, but far to less.
And sorry, but I don't like the whole school-book style with little summarizing words next to the text. That's what headlines are for.

Anyway, back to lace. I thought that I could immediately start a lace shawl since I had brought 4 balls of Kidsilk haze, but I guess that would not be enough for most of the shawls in this book!
Most (all?) use Jamieson and Smith yarn. Probably the most expensive wool yarn I ever saw. Is there something special about it? I mean apart from the fact that the cobweb(wow!) and lace is well, lace and cobweb? Couldn't I substitute it by machine yarn of similare weight-yardage ratio?
Or can I somehow use the kidsilk I have for one of the shawls? Hmm, some math needs to be involved. Plus I had intended to make something more like a stole(rectangle) than a circular or triangular shawl. Not that I don't like them, but I haven't at all worn the triangular ones I have, but then they are not as big as the ones shown in the book...which also explains the amount of yarn needed.
Anyway, probably can't buy any yarn this month. Eventhough I did get my financial aid on time, I have some other things I need to spend it on. Like getting a hair cut, which is really badly needed! And I intend to save some money(90€ to be correct) for the fees that are coming next semester(thanks CDU).