Excellent suggestions. One response to "Why?" With quilting you are sewing together many relatively small pieces of fabric. Larger seam allowances lead to bulk - often in very difficult places - and a heavier quilt all around. 1/4, I believe, has evolved as a good compromise between a sturdy seam and an acceptable amount of bulk.
Ron, From Blue Mountains. I've wondered - do you, and the rest of the world, call it a 6 mm seam or do you, certainly outnumbered on this post in several ways
, adapt to the American antiquated system of inches?