Hi - I'm lining a 16' straight chimney. It is in pristine condition, 10"x10" ID tile, ~2" air gap all around tile. The stove is a VC Resolute Acclaim. It will be installed on the hearth in front of the existing fireplace. Permit is pulled. At TSC I can get Simpson DuraTech SS double wall HT2100 for the same cost (3'=$70) as 316L Rigid liner including insulation. Flex is a little less.. So the question for the board is FLEX+ Insulation, SS Rigid + Insulation, OR SS Double wall? I have no experience to guide me. I'll have scafolding up from the chimney brick work so it is an easy install. What would you do? What issues should I be looking at? I'm building my scaffolding from timber on the site this weekend. Scaffolding will then become fuel once project is completed. Cost a box of 6" lag bolts. THANKS!!