My suggestion is to not worry. As you know, if you keep some flame in the stove you will get more heat and yes, it will shorten the cycle but not by all that much unless you give it a lot of draft.
With the rolling flame and looking like the pits of he!1 itself, that will not shorten the cycle. In fact, if you turn the draft down to where you have no flame, most times, with a full or nearly full firebox, you will come back later and see that the rolling flame is there even though you had it down. It won't last too long and won't shorten the cycle or at least that has been our observation.
Not sure where you have the draft set but with our stove about .75 seems to give the best results. That is, enough heat to keep us warm and yet a long enough burn so that you don't wake up to a cold house. We have tried setting the draft lower but what we then find is that the stove is not all that hot and there is a huge amount of coals and not yet burned wood. Of course, simply giving it more draft takes care of that.
I suggest you experiment with draft settings perhaps a .5, .75, 1 and 1.25. See how long the fire keeps with the different settings but you'll have to do it more than once because other factors come into play, such as the type of wood, the size of the wood, the outside temperature, wind, etc, etc.
Also when the burn gets almost down to all coals, we then open the draft full. Sometimes we will even rake the coals which will help them burn down faster.
Naturally the type of wood has a huge effect. This is why we keep our oak for the cold January and February nights. Also how you load the stove matters a lot. We try to have not a huge bed of coals before we load up for the night so that we can get more wood in. Then we move the coals to the front (daytime we just spread them). Then the most important piece of wood goes in the bottom rear. This could be a large split or round. This piece is the key to holding longer fires.
In addition, when splitting wood I like to split a lot so that we end up with rectangles and/or squares. Looking at the picture below, notice the ends are built with squares and rectangles. We really like these for that bottom rear. Most times we will have very few coals under that piece and will have it tight to the rear of the stove. We do this even when the weather is not so cold, like lows maybe in the 20's. Usually with those temperatures we do not necessarily fill the stove but it will give plenty of heat so that we wake up to a house that is still in the high 70's. Then we add wood and get the temperature to around 80. Plenty of folks winch at those temperatures but this is how we keep our home all winter long.
That stove will go 16 hrs. on low and still have some coals in it.
