At the Hattiesburg quilt show there were over 400 quilts - and believe me they were absolutely GORGEOUS - BREATHTAKING as a matter of fact - lots of originals, art quilts, log cabins, the Hoffman challenge.... and if you stuck your nose right up on the quilt - guess what - lots of seams didn't match... stars were kinda wonky - etc... but believe me, the main focus of each and every quilt was NOT "do the seams match perfectly?"
Now that doesn't mean that a half inch off is in the ballpark but come on - give yourself a little leeway!!