Looking ahead to when I clean my chimney this spring - I want to disassemble the double-wall Excel pipe above the stove. When I removed one of the screws a while back (put in by installer), I noticed that based on the length of the screw, it is possible the screws are penetrating the inside pipe? Do I need to worry about lining up the piping so I use the same screw holes? If not, will the smoke exit those holes? If so, where will it go - does it end up making it inside of the insulated excel piping above?