Having a carbon monoxide detector would seem wise.
In reality, if the fire is left on a reasonable draw, i.e. plenty of air is entering, supporting combustion, and leaving with the hot gases via the flue, there should be no problem at all. The problems only start when people shut down the stove, restricting the airflow, to keep the fire in over night etc.
When you say shutdown the stove, does it mean the front stove door or the pipe damper?
Should both be kept open?
On most stoves there’s an adjustable air vent at the base and on some a damper in the flue. The damper should never be closed completely or the gasses have no way of escaping except leaking into the room/tent. Ideally, the flue should stay partially open and the draw vent not fully closed. It will burn more fuel but be safe.
Modern household stove no longer allow complete closure to prevent unburnt gasses getting into the atmosphere.
Stoves differ so much. If I were you I’d do some experimenting (in daylight) and find out what works with yours.
We can’t give you any hard and fast formula at a distance.
You are going to have to find a balance between air input, flu output and fuel loading.
60mm is tiny for a flue, I can't imagine why anyone would reduce it that much?. I have seen a wood stove smoking excessively when the pipe diameter was reduced to half by the pipe reducer (127mm to 60mm) even with the front door air vent fully open.
No stoves are fully sealed, if they were, there would be no oxygen getting in & the stove would go out.Came across this youtube video. The presenter makes his own woodstove, and runs it over night in his small cabin while sleeping in it.
Would it be safe in doing so? The woodstove seems huge, and not fully sealed for the smoke either.
60mm is tiny for a flue, I can't imagine why anyone would reduce it that much?
You noted that the stove wasn't sealed. If there is reasonable airflow into the cabin, then there should be sufficient oxygen entering the stove to prevent carbon monoxide forming
The farce is the regulations here require you to have an external air vent into the room for a stove over 4.5Kw (IIRC). We had a new stove put in a few years back, we live in a 350+ year old barn, stopping the drafts is impossible! I sealed the external vent up as soon as the fitters had left
I cannot speak about your specific installation but I think that there is a big difference between a system designed with a 60mm flu and one designed with a 127mm flu that is choked down to 60mm especially if the air input isn’t balanced with the flu output.I have the other smaller portable woodstoves using 60mm pipes with 90 degree elbows, spark arrester and rain cap. These bits were very pricy for 127mm flue, but cheap for 60 mm, hence I got the 127 to 60mm reducer.
I cannot speak about your specific installation but I think that there is a big difference between a system designed with a 60mm flu and one designed with a 127mm flu that is choked down to 60mm especially if the air input isn’t balanced with the flu output.