Skeat, I learned during the Blue/White Star swap and the original Challenge Block swap that the quilterscache. blocks sometimes REALLY do have problems. They DON'T always measure out exactly the size they say they will and it is NOT anything you are or are not doing.
I have thought about the size issue for all the swap blocks I've gotten back and here is my thought for- what its worth. I love doing the swaps, my friends put their heart into the block and I appreciate them no matter what the size. I am going to just use a setting for them that will allow me to add either a tiny bit or maybe more (if needed) of sashing to make them all play together nicely. For instance, I may put them on point and by adding fabric to the corners to make them square..then they can be ANY size I want! :lol: I'd love to have one of your blocks Skeat!