Ok at the chance of sounding like a total beginner I am going to ask this question...everyone suggested finding her smallest block and using those measurements for squaring up the rest of the blocks,,,,,ok assuming the rest of the blocks are the right size why wouldn't you just redo the smallest one?
Mimi thank-you for posting I learn from all of you that are braver then I.

I'm sorry, it's not a quilt as you go, it's one of Eleanor Burns' rulers specifically made for squaring HSTs.

I guess my fingers were typing faster than my brain was thinking.

Definitely square them up. Pinwheels are a hard place to start. I was quilting over a year before I could get them to match up. Don't get discouraged. Practice, practice, practice. Fortunately, practicing quilting is fun.

After years of frustration I bought a Eleanor Burns square up ruler - ahh, end of problem. Who says they have to be a certain size -- oops, I forgot all about the Quilt Police.

I looked it up on google and all I find is flying geese rulers and fussy cut rulers.

go to www.quiltinaday.com; choose Shop Online; choose Rulers & Templates, then scroll down to 6 1/2 Triangle Square Up Ruler by Quilt in a Day.

If your HSTs are larger than 6 1/2", there's also a 9 1/2" Square Up Ruler.

How do you square off from the middle?

Instead of tracing templates and cutting, invest in a rotary cutter and cutting mat as soon as you can. You don't run the risk of stretching the fabric as you trace around your template, plus, if your pencil isn't sharp you will have a thicker line to cut through and end up with shapes of different sizes. Also, when you press, especially on the bias, make sure you are using a dry iron. Steam will stretch your bias seams.

I would square them up, for what you have done, then make pinwheels by taking two fabrics face to face, the size of the square you want, sew 1/4 completely around all four sides. Then cut corner to corner on the diagonal. then take that 1/2 triangle and cut it corner to middle of the long edge. It's so easy, I just hope I explained it so you can understand. I'm planning on doing a pin wheel soon, but have so many others I have to get done first.

Thank you very much