I had my cupola in year 1 of my sugarhouse, no hood, in year2 I added the hood and ran the steam stack into the cupola. Then 7 years later I got my 3x8 pan set which came with 2 steam stacks, I continued venting it into the cupola because I liked how it looked and functioned. I had my steam stacks both suspended from in the cupola. My hoods had 2 stacks 15" diameter that went up towards the cupola and terminate about 3' below the cupola, then in the cupola I had 2 stacks 13" that hung down and into the 2 15" stacks below. The overlap was about a foot. This way I could raise the hood when needed and the stacks just overlapped more.