Stove Pipe for older Resolute Acclaim I

[meanjoeg]

My wife and I recently acquired an older V.C. Resolute Acclaim, replacing a V.C. Scandia. The collar that the stove pipe sits in is 6 1/2" x 5 1/2", and I'm wondering if a 6" pipe was meant to distort into the opening, or is there a specific pipe for this (oval to round)? I would like to use 7" pipe, as the manufacturer recommends a min. 6". The opening into our masonary chimney is for an 8" pipe, so I was going to use a reducer from the 8" opening to the 7" pipe, unless this stove is meant for a 6". Any help or instructions would be greatly appreciated.

 

[meanjoeg]

Something else - in the picture of the stove to the left, you can see the reducer I intend to use going into the 8" hole. Is this going to enter into the thimble enough, or do I put a small section of 8" into the hole attached to the reducer?
Thanks Again