Info on masonry chimney flue and stove size.

Forget about the stove questions for now.... You want to what?
You better check with the building inspectors dept. first..... They usually don't give permission to occupy till the structure is completed (per the submitted plans)

You did pull a permit didn't you? :lol:
Sorry had to say the permit thingy...

Interior 8/8 flue location is about as good as it get for wood stove to masonry application.
Me ,I'm a Vermont castings suporter. I think would would be best served witha medium range stove 40,000 to 55,000
BTU range My vote would be for the VC encore of Dutch west. Economic choice the Englander manufacture's line

You did not identify your location so climate also plays into your choice.

in 30 years I have saved over 25,000 galons of fuel none of my stoves had a blower

The R-50 is a sort of myth, you can read about it here. They perform around R22, which is excellent for foundation walls and provide other benefits like better moisture control in the basement. R22 reduces the heat loss to a mere 2.27%. If it were R50 it would reduce it to 1%, there's not a big difference between R22 and R50 in heat savings, but there sure is in price!

The living in the foundation while you build your house thing being illegal in some states I was told a few months ago is because of neighbors. People would pour a foundation, cover it with plastic, and live in it for years, stuff all over the yard and neighbors were not happy having to live next to that for years. They united and got it outlawed to do such, or at a minimum limit the amount of time allowed. That was the reason I was told, sounds like in PA they still let ya do it

What are you doing for the rest of the walls? If I could make a house, I'd use 2x6 walls filled with wet blown cellulose (has to be applied before drywall is put up) and cover the entire outside with 2" polyisocyanurate foam board. That prevents short circuiting, part of the "Warm Wall" system, and net me around R30 average for entire wall. Or, the cheaper route is 2x4 walls filled with wet blown cellulose, and the outside covered in 2" XPS foam board. That should be around R20 for the entire wall.

The problem with batts is they need to be installed properly which, is nearly impossible. Each piece needs to be fluffed, not have rounded edges, fit square, not be compressed, and be cut to fit like a glove around any obstacles. Just a 1% gap around batts is devestating to its effectiveness, and I recently found out the R-Value of batts decrease as temperature difference increases. You can read another post started by precaud, where insulation is discussed. There's pictures from my energy books, and experiences using batts vs. cellulose in there.

Cellulose in material costs is much cheaper than fiberglass, the wet blown you'll have to get that professionally done. Wet blown is great in walls as it will never settle, it prevents air channels, slows air movement, helps slow air leaks, and best of all is nearly impossible to install incorrectly. But, you have to leave the walls open for a period of time to let it air dry before closing them up, and it should be done before your floors because they usually use a spinning brush to scrape the excess off. I imagine the cheap cost of cellulose, and speed at which it can be installed, paying a professional will be comparible in price to the high cost of fiberglass and no labor if you do it yourself. The next best option, is to fill the walls yourself with dry blown cellulose which is easy to find and easy to rent the machines, you dense pack it to avoid settling. Last, is to use fiberglass batts try your best to install each piece carefully and precisely. In the attic, definetely go with dry blown cellulose instead of fiberglass, rent the machine and do it yourself. A 2x4 wall with 2" XPS foam on the outside, and cellulose blown insulation inside will perform significantly better than a 2x6 wall with fiberglass batts and take up the same space. The foam prevents short circuiting, and lowers the temperature difference inside the wall cavity letting the insulation in the wall work more effectively, plus is a better sound barrier.

Option: go to www.regalind.com and check out the "Regal Wall" link giving you some instructions. It's a method for putting cellulose in sidewalls dry instead of wet. Both perform the same but the D.I.Y. can install it using a basic rental machine vs. having a pro come in with what is a much more involved wetspray system. You just have to make sure you blow it in consistently and with sufficient density from bottom to top of cavity to keep it from settling. If Q's, call 800-848-9687 x 216.