I wouldn't recommend seams narrorer than a scant 1/4", for all the reasons stated above. Your quilt center will come out a few inches smaller, but you can make it up by a wider border. Good luck!!! I'm sure you'll do fine. My 2nd quilt was a queen size that I didn't have a pattern for, after my first, which was only 49x49. Quite a difference, but it all works the same, just a different size.