Considering rocket mass heater with in floor ducts for second story

Hello all, I appreciate so much the time spent giving advice and thoughts, ans sharing your wealth of knowledge and experience!

I have a 2 story unfinished garage with a loft upstairs I plan to make into a living space.  Located in SW colorado altitude 6800 ft.  
There is an existing woodburning stove that is pretty old and ineficient.  The heat does not get upstairs or really even past 6 feet around the stove. There is currently only insulation in the roof.  The upstairs floor is just a layer of plywood.
I had this idea that i could use input on:

 If I replaced the woodburning stove that is downstairs with a rocket mass heater, and ran the ducts along the downstairs ceiling, would it work to heat the place?  Maybe 2 along the inner area. I mainly want the upstairs warm but the downstairs is a workshop so it would be a bonus if all were to be heated.  I want to make a plan before installing electrical, plumbing and insulation.

Floor area is 25x 29 ft.
The  ceiling/floor beams give me 9" of working space for duct and thermal mass.
The current exhaust pipe size is 8"

Do I have enough room to properly insulate the ducts to keep the heat going?
What would be the reccomended exhaust duct size and what would be the recommended insulative material?
Please see photos for more detail.  If more info is needed, I will provide.

Hi M;
As I understand it, I don't think your plan will do what you are hoping. (I could be wrong)

If part of your plan is to insulate the whole building, what I suggest is an 8" batch box with a brick bell.
I would cut registers into the floor upstairs to allow free movement of the heat, and fans of course as well.
Rocket mass heaters are moving away from the J-Tube design with pipes thru a solid mass, to a Batch Box design with a hollow "bell"  (bells are commonly brick but can be metal lined with brick or covered by cob or brick)
Your shop will be warmer than the upstairs, but as heat rises the whole building will be very comfy.
It would be nice if your chimney went straight up rather than a double 90 out the wall but what you have is completely usable.

Here is a link to Peter Bergs Batch Box site to learn all about them.   https://batchrocket.eu/en/