Thanks, for replying, Peter. I appreciate your time.
But it's like when you have a cold: you put off going to the doctor until
the last moment, then as soon as you do, you start to feel better.
I have more or less solved the problem I asked you about yesterday, so
please don't spend any time on it.
In the end I copied the Left Hand Side running head (black type color) and
pasted it to the center of the right side of the two-page spread (in each
Master Page), opened the Type mode, retyped the copied running head to
match the content of the (gray) RHS, deleted the old (gray) RHS running
head, and using Smart Guides repositioned the new RHS running head in its
place. Times twenty.