Regarding 1/4" seam.....it may not be you - what machine do you have? The only machines that have totally accurate 1/4" seams are Pfaff nd Husqvarna because they are SCANT 1/4" seams.....I have made over 200 quilts and god knows how many other items and used to teach. I cannot make pieces macth on my mothers Janome in particular..but the other brands like brother, elna etc seem to be just as bad!
Sorry to anyone out there that sells them..just my opinion of course!
My suggestion..make sure your foot is sewing a SCANT 1/4" and bend the little guard till it is if you have to!