Stove pipe/baro install for LL Hearth model

Would like some advice on best stove pipe setup for Hearth model into my fireplace. The fireplace opening is approx. 35 inch wide by 29 inch high and the damper is approx 4-1/2 wide.
The depth to the damper from front fireplace opening is approx 13 inches. The stone fireplace hearth is exactly 24 inches wide. I plan to install a baro damper and know how to seal off the damper throat with a piece of plate/sheet steel. Need help deciding the following:
1) Where do I install the baro damper for best performance and will I be able to access it?

2) What is the best setup for getting thru the 4 inch damper and how far above the damper do I have to run the stove pipe?(above my damper the chimney tapers upward 3 to 4 ft before transitioning to flue liners) Do I have to run pipe as far as flue liners or just a few ft beyond damper throat?
My thoughts are that I may use a 6 inch round to oval adapter just below damper throat and then use oval shaped or flex pipe to go thru damper and up the correct height. If I run a few feet of oval shape pipe above damper will it's shape vs round have any effect on the draft?

Any help appreciated , thanks.

First let me qualify my advice, never done this for myself but have helped a few folks through it who bought my stoves.

1. I would put the baro just above the Elbow that transitions the stove flue from horizontal to vertical, that way you can slide the stove out to adjust/check on it.

2. Lots of folks use insulation to seal around the pipe after installing it to prevent air leaks (both in and out), the oval pipe idea sounds good, or you could carefully squash the 6' flue pipe as the folks I have helped did. IMO it should go past the smoke shelf by at least 6" if that gets into the flue then so be it. And no the oval or squashed pipe will not affect your draft.

Have fun, I'm sure others will chime in with their experience.

Hi Majortom6x,
Place the baro where it's easiest to get to. I would use the flex pipe idea and go about 2' above the damper. Make sure no gases can come down the chimney past your damper, seal it off good and tight.
good luck,
Jer