I was able to locate Comet McNaught this morning (Jan. 3.49UT) in very
bright twilight using 15x80B. With the Sun only 7.3 degrees below the
horizon (comet 3.6 degrees up), my own description pretty much matches
Bob King's: a relatively easy, very small, dense, almost planet-like
body 8 with soft edges and of DC 8. It reminded me very much of my
final pre-T view of Comet Ikeya-Seki 1965f at dawn just week before it
rounded the Sun. In both situations, due to the very advanced state of
twilight, only the center-most region of the comets must have been
visible to me.

No comparison stars were available (my eastern view was largely
obstructed by trees and even the comet was seen among tree branches!)
but from experience in making similar observations, I'd judge the comet
as not fainter than 2nd magnitude.

JBortle