Interface changes: I disabled subtitles because every time Lea commented, the subtitle screen came up and interfered with the window where I was entering symbols (this may have been because by default the window for entering symbols was near the bottom of the computer screen).
I opened the window that showed all the Generals and put it at the smallest window size. This way I didn't have to move the mouse pointer so far to get from one General to the next. I also found that the smaller window made me feel less nauseated when swinging the camera around to aim at each general. I closed down the other two viewing windows and the map to eliminate distractions.
I moved the window for entering the symbols as close to the viewing/aiming window as possible, so again I only had to move the mouse pointer a short distance.
I changed the setting in the Options menu to "Snap to Grid." I'm not sure if that made a difference or not -- I may just have been better practised with the camera by the time I made that change.
More ideas:
I figured out exactly which General I would be facing next -- there is the same pattern for the sequence of challenges. For the hardest part of the sequence with three Generals, the first answer for each General seems to be "AA." So as soon as the first General started, I shot "AA" at him, then "AA" at the next General and "AA" at the third General. By the time my answer got to each one they had started their question, so it worked. After the third "AA" I aimed the camera right at the General I knew would be asking the next question so I could respond immediately.
EDIT: Other ideas -- you can play around with the mouse sensitivity in the Options menu too -- I found it responded best with the button pushed to the far right, but that's probably an individual preference.
Also, I found that it was easier to aim the camera/viewing window if automatic tracking at the top of that particular window was enabled -- if I disabled automatic tracking, the camera angle tended to drift back into a position under Lea's chin.

Ronrob -- are you going to give the Generals another try?
