Everything seems to have blocked beautifully (initially, I had some curling in the edges even though I added garter stitch as suggested). It has stretched to about 63 x 30—it was original in the vicinity of 48 x 20. I could have blocked it more aggressively but I don’t have a good place to block to really get the pins in so they don’t move.
This wool probably has somewhere between 160-200 yards in each skein. I have no idea. That’s why it’s mystery wool! I used about 2 skeins of it with very little left.