I just read a Marti Michell technique where she folds the fabric and does one seam at a time instead of pivoting. Unfortunately the info was in a template pack so I can't share it. You might try go ogling Marti Michell and y seams.
My secret to precision is to not sweat it. Strive for it, but most people won't care about your perfect points and corners. And if they do, they aren't really seeing your quilt, just being picky, so stop showing them
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