Here are my finished welts. I've topstitched them all around. For my sew-alonger, this will be much neater and easier than the craziness shown on Pg. 62. Rather than topstitch the completed welts into place I will handstitch them from the back side with diagonal stitches.
Here I've chalked marked the slash marks, checked and re-checked them to be sure the welt flap will cover them when flipped back into place.