But did I listen? No!
She was right of course and I have learned by doing that sheeting is a challenging cloth indeed. My needle test did not take into account the doubling effect of cloth weaving. Nor did my running stitch predict the challenge sheeting would pose to a fine back stitch.
Still, I'm too far in to give up now.
By the way, I somehow miscounted the squares (which are 1 1/2 to 2 inches to a side). There are 16 rows of 10, not 17 rows of 11. So, having now stitched 40 squares, I'm one quarter of the way through ...