New here too and with only a little over a month w/CI2600 probably can't offer much but here's my take:
I try and get a good load of wood going about 11-12PM if I want it to go all night. I close down the cat. damper and air ctl. as suggested. About 6 hrs later when I come out to fire it up again, I've found the temp. anywhere from 300-500, usually somewhere in the middle. I open everything up, give it a few minutes to get some air, depending upon how much red coals I see may stoke it a little, may add a little kindling, load in some wood, just push the door too for a short time, give it a little time to catch and off we go again.
I don't know if the cat. is still active at below 500 or not, all I've read says probably not, it should be some where between 500-700 to be active. But I don't think they expect us to get up at 3 or 4AM to load more wood to keep the temp up, hope not, in any case it "ain't happen'."
I don't know how people are getting loner than about 4-6 hrs. of usable heat out of these things cause I'm not. So far I've not been impressed w/the amount of heat out put after about 4 unattended hrs., its marginal and we're only trying to heat about 1K sf. We do a vaulted ceiling however so that doesn't help. The best I hope for now in the AM is enough residual heat and coals to start it up again and so far that has not been a problem.
Sorry for the ramble, hope this has answers some of your questions. BTW, what model do you have?