I have made a 9 block square using 4' squares. My finished block measures from 10 1/2 " to 10 3/4". Should I trim all of the blocks to 10 1/2" or smaller? I am going to put a 2" border around them also. Thank you in advance for everyone's advice.

If you are going to add sashing and the individual pieces of the 9-patch don't need to be aligned, you can trim them all to be 10 1/2."

Yup, just pick a number and trim away!! This is a great way to learn how to get that 1/4 inch that we all struggle with.

I agree, trim after adding the sashing. I would love to see a pic when you are done.

I would trim and then add the sashing. That way your sashing all lines up nicely :D:D:D