A piping question

[epd0407]

Im piping a new Mason 2x4 in a brand new sugar shack. I have a 6" question for you all.

I went to HD and picked up the triple wall through the wall kit along with all triple wall pipe. Within the wall kit, it came with a stainless steel collar and a 6" crimped on both sides short length of single wall piping that locks into the triple wall within the wall thimble.

This 6" double crimped piece does not fit into the collar on the arch. I can put the stainless collar around it and clamp it. How is this connection normally made? Should I just go buy a double wall stove adapter? Will this solve this issue?

[BreezyHill]

We used insulated pipe one time back many years ago and it burned thru in 7-10 days. So we run stainless for the chimney and run it through a larger sized tee thru the floor above and the floor joices have a flashing face plate set about 1" away to protect them...with no issue for many seasons. With the remodel of a new metal ceiling a 10" tee with 8" pipe thru it for the smoke and the tee has never gotten so hot you could not hold your hand on it. Cool air comes down thru the tee as steam is leaving the sugar room.

My house burned to the ground as a kid so I am very fire cautious.

Ben