The offset adapter will complicate sweeping the liner. Sweeping from the top will leave creosote crumbs in the offset, that you have to clean out through the box (if you don't want to pull the insert to clean.) Sweeping from the bottom with a Soot-Eater will be out, I think. If you have room to put the damper in the appliance adapter, you can just run a rod to the front, no sprockets or anything complicated. Or maybe if you are going to leave the surround off, you could reach the damper handle with your hand. Looks like it would be an arm-scorcher though, unless you have a welder's sleeve you could slip on your arm.
I don't think nosing the stove out will give much more heat. Are you using a blower? That should pull the majority of the heat off the box. But their "natural convection" design seems like it should work pretty well, so I can understand you wanting to bring the stove out to take fuller advantage of that. Or maybe you can use a couple of small computer fans blowing toward the air ducts to enhance the movement of heated air out of the fireplace?
Ah, you know your woods I see. Maybe you have a different type of Maple in MI that I haven't seen? The soft Maple I see here (Silver or Red) has more flaky bark, not blocky like in your pic, and the hard (Sugar) Maple can even approach White Oak in the flakiness of the bark.
The Buck 91 cat probe comes in from the front and the tip of the probe extends slightly over the face of the cat. Even though it was 6", it still transmitted temps very well. I generally ran it around 1200 or so, but saw it pushing 1800 a couple times, before I got better control of the air.
In retrospect, instead of tweaking the air intake on the stove, I'd have been better off just putting a damper in. Woulda been pretty easy...
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The Fireview and Keystone, on the other hand, have the probe coming in from the back, and the stock probe doesn't reach to over the cat face. I tried a longer 8" probe, but it still doesn't transmit the true temp. To get a short probe over the face of the cat, I would have to drill through the top stone and the cat heat shield. Since I have a surface meter on the tee, and the probe actually gives me temp conditions around the flue exit, I run the stove with those and don't worry about the cat temp as long as it's not glowing too brightly.
It looks like you would be able to see the cat glow in the Sequoia. The heat shield on the Buck blocked visibility through the door glass, but I could see the glow if I looked through the bypass rod hole in the front of the stove.
You are saying you had the bypass closed? As I mentioned, to avoid crumbling the ceramic cat, open the bypass for a couple minutes to allow the cat to cool before opening the door...this will avoid thermal shock. My neighbor had the habit of opening the stove door and throwing in a couple of splits at a time. Some no doubt had rain or snow moisture on them. His cat would crumble after a year or two. I tried to explain "batch burning" to him but I don't know if it took...