Great minds think alike, Nancy! That is exactly what I did after I "frogged"
the piece you saw in the picture. I was going to do a straight stitch on the horizontal but, once the stitches were out, there was still the diagonal fold remaining. So that made me think, "what about if I match up the stripes closest to the diagonal with the fabric of the other strip?" Then I glued it on to keep it in place for sewing... and it worked! So, yes, what you said made total sense and I'm glad to have confirmation from you that this might be a good way to go. Lois, would you believe I don't have a lightbox yet? I know how to put a makeshift one together but I'm hoping when DH builds my sewing room furniture, he will build one into my cutting area...
Okay, it's not PERFECT, but close enough for the first joint: