[if this is the wrong sub, please advise the correct place to ask my question.]

Hey folks, recently got an older homemade wood stove for my shop, set up for 6 inch chimney pipe, and I'm trying to plan the chimney. My big fear is chimney fires.

The primary fuel is going to be WMO, since I have over 150 gallons already. I am building a burner design from YouTube that claims incredibly low smoke. Would this be more susceptible to chimney fires or less compared to a wood stove?

I don't know how to cut a correct hole for a pipe that isn't going straight through, so I know I will need to use two 90* pieces.

Is it better to take the corner right above the stove and make the rest of the vertical journey [to get above the gutters, about 20 feet up] outside or go straight up inside and then turn 90*? Am I thinking of this all wrong?