Jotul Oslo Adapter

Hi all
Thanks for your help. We just got our Oslo and I'm in the process of hooking it up. The piping we have is Amerivent double wall DCC pipe. Selkirk DCC is the same. The 6" DCC double wall adapter fits even worse than I expected. What's the best way to transition from the stove collar to the double wall pipe? A 7" to 6" reducer? Thanks again!
Mike

most of the companys use a stove top adapter. I did not see one in their instructions. One thing I like to do on double wall is use ameri vents single wall to chimney adapter . I believe it is a 6hs-swa .I cut it down so that just the flange sticks out and attach my double wall to that. Probably not a strict U.L way to do it but it makes a nice secure way to install it and leaves the air gap open.