I am working on installing 10 ft of Selkirk pipe for my Tarm Install. It looks like I will need to put in 15 deg. offset to get my two in clearance near the side wall. My question is there any preffered placement for the offsets??? I only need it to get around the top portion where my collar is on the roof line. Is there any problem putting the offset near the cap area or is it better to be down further near the actual ceiling?? As usual thanks for all the great info