I exported both grid and positional themes from one menu screen hoping to apply it to the next menu screen, but it did not pick up the new chapter names and I had to retype them. I should note that I had deleted the original chapter numbers, e.g. "1:" that automatically appeared in the chapter names.

I'll retry and this time retain the automatic chapter numbers and see if it works. However, I find the chapter numbers generally take up too much on-screen space and I'd prefer they not show up at all.