Man, I'm getting right crazy in my old age. The Animas Quilts mystery design, according to their website, is built on a 1 1/4" grid. I think that even outdoes Bonnie Hunter because the last few mysteries from her only had 1 1/2" finished HSTs. Furthermore, I'm in the process of making about 300 1 1/4" HSTs (1 3/4" including seam allowances). And as I make them, I'm squaring up every one. Yes, you heard me right. Every one. I may only be slivering off a thread or two on each side, but when you have pieces that small, those threads tend to add up, and thus you have to be even more careful about size.