Both my friend and myself have Avalon wood burning inserts installed.
Mine is the Rainier whereas hers is the Olympic.

The damper adjuster on mine works as I'd expect. That is firm but not
overly stiff. Hers on the other hand are quite stiff and at times rather
difficult to adjust properly. The Olympic has two.

Curious as to whether or not the adjustment rods themselves have any
tension adjustments? If so would they be reachable without pulling the
insert out? Or something a technician might better be tasked with?