Building a RMH/reburner style wood stove for a THOW

Hi folks. I am building a THOW in Eastern Iowa that is about 174 sq ft inside and has about a 7 foot ceiling(average). So basically around 1200 cubic feet of space. I want to build a wood burning system that provides heat, but can also be used to heat up an oven or to provide heat to burners. We might also like to heat water with it if we can. We really like the idea of RMHs and we also really like the idea of the "Kimberly" stove. We basically need something that is very light, but very efficient. We certainly can't afford a 4000 dollar wood stove either, and we have the necessary skills to build our own. I used to do blacksmithing and used to build my own forges.

I'm planning to build a J-tube style heater with a fire box and heat riser lined with a mix of fire clay and desiccant crystals(SiO2). I plan to use a selective exhaust line from there that can send the heat either to an oven chamber and possibly to a water heater as well. We have very limited time to get this thing built since the cold is coming fast right now, but we're very motivated. Our THOW will be insulated with mineral wool for fire safety and we'll be lining the structure in metal, and using as much fire-resistant material for our cabinets and other interior components. We plan to have exterior air intake to the fire so that when closed it will be a totally sealed system relative to the inside of the THOW.

We would really appreciate any suggestions and ideas regarding what size and design to go with, and suggestions regarding materials and construction techniques. Size of firebox, types of fuel recommended, etc. would all be useful. We should have access to a great deal of scrap wood, and even used motor oil. I would love to have an incinerator that can handle diverse fuels, but that isn't vital. Our THOW is extremely light compared to most in its size range so there's less mass to store heat in than many, but creative suggestions in that area would also be welcome.

What's your sub floor look like? Earth or?

Lol sorry I just looked up thow

Yeah not ideal floors for using as a thermal mass. At this point we're thinking we want to use the kitchen counters and maybe some of the cabinetry overhead as thermal mass. I need to get a good idea how to proportion everything

Yeah so many restrictions right down to the tires. I would imagine a rmh will scale. I see experimenting in your future... I built mine three times inside two days so it's not a horribly time consuming process.
Also 174 sf.... Busy bodies should heat that lol

Its definitely going to be a small heater. I'm planning on using a feed system that is sealed off and fresh air intake from outside so the combustion system is totally sealed from the interior atmosphere.

I'm thinking about a 4-6 inch wide burn chamber that is about 8-12 inches long, but I am still unclear as to how tall to make the expansion riser. I plan to put an oven/burner area at the top of the barrel, and use this as our primary means of cooking. For warmer seasons I will need an alternative exhaust line though so the heat doesn't build up in the structure from the cooking fire.