[ebruchez]

You swap character by character, and of course if you want to swap a group of characters related to a particular domain you can do so. The tray is just a grid so you have as much flexibility as you want as long as you have the appropriate characters at your disposal.

I have just finished reading Mullaney’s book.

[dredmorbius]

Thanks.

The impression I'd had from the interview(s) I'd heard were that it was common practice to use a fairly standardised characterset and then the specific auxiliary set as needed. How much individual typists might move between different machines and (nonstandard?) configurations I don't know.