robertee. I commend you for your efforts.It is a lot of work! But you can expect a lot more comfort and savings for you efforts.We have to seal with mastic all joint and seams per code.But what cracks me up is that you don't have to seal the elbow gores or the little holes in the boots and fittings(wys ext).But what I find most humorous is that you don't have to seal between the boots and the floor or ceiling.I use a skill saw when I cut out the floors because I can get a lot nicer fit.Reciprocating saws are a excellent
tool BUT are not known for there precision.You should see some of the kinda square kinda 4"x10" or 12" 14"that get cut in on the new constrution around here.The amount of leakage here is quit large.
Have a good day you guys.