That seems pretty simple. I might just do it myself rather than get the “professionals” to construct something that fails. Know where I could purchase a new gasket mellow?
Yep, as mentioned your dealer should be able to order it for you, I would get 2 so you will have a backup on hand. Might as well get a gasket for the cat and the door as well while you are at it incase you need to service the stove at some point, better to have these consumable parts on hand than waiting a few weeks with a cold stove.