akennyd, the problem with your question is there really is no good answer. The lower limit for you will be vastly different than that of someone else, unless you can find someone with your stove, your climate, your chimney, your wood, your wind, etc. etc. etc. As for what can happen when you reach that lower limit, well that would be snuff, backdraft, puffing, creasote build up, smoke detectors going off, etc. But what that lower limit is, is subject to so many variables. I would suggest experimenting a bit, do it during the day, monitor the smoke, or lack there of, the stack temps, the stove temps, etc.
Many here have a thermo on their stove, me included, but I use the look of the fire, what the secondaries are doing and the like along with the temps to make needed adjustments.
The better seasoned the wood, in general, the lower you can set the intake. Of course that also depends on the type of wood as well.
Have fun with the stove, learn it when you have time, don't experiment overnight, do it during the day, then apply that which is learned to the overnight burns. The best way to learn is to do. If you rely on others experiences without taking into the consideration the many variables you are IMHO more at risk of having an adverse situation than taking "baby steps" from where you are to find out where you can/should be.
So many people want to use a number, be it a temperature, or a setting, and when they try to achieve that they are not happy with the results because.."Wally the Woodburner" sets his on (blank) and when I do (blank) happens. You know what I mean. Enjoy the warmth, the learning curve can be shortened a bit by getting advice but it will still be there. Heck there are people on here that have to relearn the 5, 10, or 20 years of woodburning knowledge because a set up or a stove change.
Good luck, have fun, and let the learning start.
Oh and Merry Christmas to you as well

!!