I am a firm believer in a scant 1/4" s.a. for accuracy in the size of finished blocks. However, this brings up another delima. I have Harriet Hargrave's first "Quilter's Academy" where she advises to avoid moving the needle position. I have also heard this from a teacher on You Tube.
Whether moving the needle position or not, how do I heed the advise on one of these posts that we should not watch the needle or the pressure foot when sewing a straight seam. This seems to require a quide of some kind to follow. I do use an adhesive quide, but it needs to be moved for diagonal seams or where you might have to use pins. Hope I am making myself clear. I am sure someone here has some thoughts on this.