I've had this problem and I believe it happens because of the weight of the white fabric. Usually it all disappears when it it's quilted. Make an extra block using all the tips you have been given. Then go ahead and sandwich it and make a practice mini quilt. Quilt it and do a quick binding( just zig zag the edge). Throw it in the wash and test it all out. If you're happy with how the test looks, then it's full speed ahead.