Now, I've found this sturdy chalk marker and I've relaxed in my whole marking/matching endeavors. Once again, patterns are 'suggestions'. It's an art; not a science, so if the marks are in approximately the same general area and the overall appearance works...well, 'Bob's your uncle and get going sister-friend!' Life's too short for worrying about matching dots exactly.
At least I got to practise my button holes, and when I did do it the second time, I took my time and paid attention to every last detail. Yay.