Weaving with Thick Yarn
I know the yarn you are asking about and it is truly lovely, a great favorite of knitters. The merino in it will give it a tendency to full quite a bit, a factor that will affect your chosen finishing method. At 150 yd/50 gm, the yarn is about 1,300 yd/lb (50g is about .11 lb; divide 150 by .11). In weight, this is finer than Harrisville Shetland, but it is so lightly spun that it is thicker. Your wrap of 11-12 ends per inch would suggest a plain-weave sett of 5 or 6 ends per inch. Because the yarn will full, I’d start with 5 ends as a plain-weave sett, closer for twill.
You could opt for plain weave, in which case I’d use the space-dyed yarn in the warp and the solid color in the weft. If you sett the yarn at 5 ends per inch and you have one skein (150 yd), you could plan a 3-yd warp for a scarf, therefore 50 warp ends, and a weaving width of 10 ends per inch. You’d have enough yarn to weave a bit of a sample on the scarf warp to wet-finish so you can determine if a closer sett (6 ends per inch, say), would be better.
Another option would be a simple log cabin using your two colorways in the warp (which would give a plain weave structure but a bit of pattern interest) with the same considerations as above.
A third option would be twill–straight, herringbone, plaited, or other–again using the space-dyed in the warp, the solid color in the weft. I’d start with a sett of 6 ends per inch, weave a small bit to wash and test, and then change if necessary.
And even another option is to use your two skeins as warp and a finer yarn (JaggerSpun Superfine Merino, say) in the weft. The sett in that case should be closer so that the fabric is warp-emphasis, maybe start with 8 ends per inch. A simple twill will make the yarn the focus of the piece. You could alternate the two colorways in the warp or design a simple stripe arrangement.
Send a photo when you are finished!