Your block is drop dead gorgeous and wow what a spectacular quilt this will make. If the rest of your blocks have the same visual impact as this one I really don't think anyone will notice that the corner design doesn't match up exactly. While barely noticeable, obviously it bothers you or you wouldn't have posted. I would recommend marking the wrong side of the fabric where your miter should go (both strips) or pressing the miter fold in so you have a guide to sew. This way you can "fudge" it about until the designs line up perfectly. Then pin or even glue the printed border to your block and use lots of pins. Think it is pinned enough? Add 3 more, especially in the critical areas like at the end where you want to stop and start. Then you can use elmer's school glue to hold the miter in place while you sew.
Jenny does a lot (or maybe even all) of her stuff by hand. Hand piecing gives you a lot more control and ability to manipulate the fabric to line the designs up perfectly. So another consideration is you can hand stitch your miters and then if you wish take it back to the machine and restitch over the hand work as long as it lined up to your liking.
Rate your work on your own merits as you will make yourself crazy comparing yourself to others.