Your choice of pattern is really cute. It doesn't look very lacy, the knitted fabric looks pretty standard. The site said that the Montage 8 ply was knitted on size 3.5-4mm needles which would be American sizes 4-5. So I think that would be like a sport weight yarn.
I noticed on the pattern information that it said, "easily adjusted for other size and weights of yarn". So hopefully it gives some clues about how to make those adjustments on the pattern. Do you have the pattern yet?
The yarn is 100% wool and reminds me of some of the Noro
yarns I have seen. I think one of those might be a good substiture. Here is a site (there are many more) where this yarn is shown. I noticed it says, "Use with Fiber Trends patterns", in the info about this yarn. Look around, I think these Noro yarns come in different weights and the one shown on this page may not be the closest one to the Montage that you could find. The one on this page says size 7 needles so it sounds a little heavier than the Montage. I have never used any of these yarns, so I don't have any first hand experience to pass on, just trying to help.
If you do get a weight of yarn a little different than called for you will want to find a needle size that gives you a fabric you are pleased with, that has the kind of drape you would want for a shawl. If the gauge called for is not going to work for your yarn be sure you make adjustments.
What about Lorna's Lace or Laces, something like that. I think it comes in vareigated colorways too. It's another one I know of to check out. Good luck.