  Line-intensity mapping (LIM) experiments coming online now will survey
fluctuations in aggregate emission in the [C II] ionized carbon line from
galaxies at the end of reionization. Experimental progress must be matched by
theoretical reassessments of approaches to modelling and the information
content of the signal. We present a new model for the halo-[C II] connection,
building upon results from the FIRE simulations suggesting that gas mass and
metallicity most directly determine [C II] luminosity. Applying our new model
to an ensemble of peak-patch halo lightcones, we generate new predictions for
the [C II] LIM signal at $z\gtrsim6$. We expect a baseline 4000-hour LIM survey
from the CCAT facility to have the fundamental sensitivity to detect the [C II]
power spectrum at a significance of $5\sigma$ at $z\sim6$, with an extended or
successor Stage 2 experiment improving significance to $48\sigma$ at $z\sim6$
and achieving $11\sigma$ at $z\sim7.5$. Cross-correlation through stacking,
simulated against a mock narrow-band Lyman-break galaxy survey, would yield a
strong detection of the radial profile of cosmological [C II] emission
surrounding star-forming galaxies. We also analyse the role of a few of our
model's parameters through the pointwise relative entropy (PRE) of the
distribution of [C II] intensities. While the PRE signature of different model
parameters can become degenerate or diminished after factoring in observational
distortions, various parameters do imprint themselves differently on the
one-point statistics of the intrinsic signal. Further work can pave the way to
access this information and distinguish different sources of non-Gaussianity in
the [C II] LIM observation.
