thanks all for your advice. There is clearly a learning curve for me. I did a little of everything - remade a couple of blocks, fudged a bit, and accepted non-perfectly matched points as "good enough". This was my first experience with HSTs. the instruction said to cut squares, put a line on the diagonal and sew a scant 1/4 inch seam on each side of the line. (I think this was after sewing thesquares together on one edge). Im still not sure what scant meant.
If there are any tricks to working with HSTs, I would love to learn them