I currently use single wall stove pipe that has the seam, with this I use two adjustable 90 degree elbows in different spots. The elbows are not used as a 90 they are used to supply an offset from the wall and line up with the ceiling support box. My question is will the adjustable elbows work with single wall pipe such as "durablack" from Duravent? Their elbows are not ajustable and for my setup I have to have the jogs. Will two forty fives supply the same amount of offset as an ajustable elbow? Thank you.