Hi Catrina;
Welcome to Permies!
Well I'm the
RMH guy but I'll talk with you anyways and I'll try not to push a rmh on you. But I
should...
Masonry stoves.
First it depends where you live.
Some states require a licensed mason to build your stove, there would be no legal, insurable , dyi kit.
In other states it is OK. Plans to build your own are available on line.
Your husband could build one with patience.
Are you hoping to insure a home with a masonry stove?
I notice you mention building tight. I assume your concern is venting exhaust indoors?
All masonry stoves are double skinned to assure that all gasses leave the building.
Possibly that might be your issue against an rmh???