I do not seem to have many problems with eaten out highlight when printing carbons from continous-tone negatives. Perhaps I have not noticed it. The one or two times I have noticed it it has been due to, or I have attributed it to, over-developed negatives.

The below might be of some limited help. I rephotographed a 8x10 carbon print with a digital camera and the quality of the reproduction is suspect.

The highlight section that is enlarged is out in the sun (on white granite), compared to the heavy shade of the foreground. There is detail in the highlights.