Cool. Something I can contribute an answer to. 56 squares. Math is more my thing than color and stuff. I have found that some patterns aren't really 45 inches. The 45 inches includes the selvage. Depending on the pattern, how well it is printed etc, I count on 40 inches and anything else is bonus. With that in mind my calculations tell me that you can get 8 squares per row and 7 rows per yard.
I admit I'm very new to quilting, not to sewing and definitely not math.