Umm... Not sure anyone's going to be able to answer this to your satisfaction (unless there is a source out there describing Caesar's sleeping habits in greater detail, which I doubt). But the historian Sallust, who knew Caesar, has this to say:

" Finally, Caesar had schooled himself to work hard and sleep little, to devote himself to the welfare of his friends and neglect his own, to refuse nothing which was worth the giving. He longed for great power, an army, a new war to give scope for his brilliant merit."- Sall. Bellum Catilinae, 54.4

The later biographer Plutarch describes Caesar's sleep habits in a bit more detail:

"Nevertheless, he did not make his feeble health an excuse for soft living, but rather his military service a cure for his feeble health, since by wearisome journeys, simple diet, continuously sleeping in the open air, and enduring hardships, he fought off his trouble and kept his body strong against its attacks. Most of his sleep, at least, he got in cars or litters, making his rest conduce to action, and in the day-time he would have himself conveyed to garrisons, cities, or camps, one slave who was accustomed to write from dictation as he travelled sitting by his side, and one soldier standing behind him with a sword." - Plut. Caesar, 17.3-4

Take both these passages with a grain of salt, though, since they come from sections in both Sallust's and Plutarch's work devoted to particularly vague and more generalized biographical sketches.