I'm a builder in France, but have no
experience building a Wofati.
Is it like a one floor house into a berm facing south with a glass construction in front that heats up the house?
And does it have a roof carrying an extremely heavy load of earth?
I think most important is the foundation of it. If you're on clay, it could be difficult to support such an extremely heavy roof.
But if it's rock based, the problem will be getting permission, and that starts with great architectural sound drawings.
What does it matter if info is US based? US is gigantic, there is so much diversity there, maybe even more than in the whole of Europe.
Everybody has to recalculate the height and width of the beams and the carrying strength they have. If in doubt over-proportionate.
You'll first have to really study some drawings, come up with your own design and then ideally attract some mad greenminded architects that like a challenge which can recalculate your ideas. Because if you need a permit for something as unusual as a Wofati, they're going to be total arseholes.
They bureaucrats are all about discouraging any alternative house building. The powers that be need you in
concrete blocks costing you half your life to pay back, while selling your soul to the system. They'd
fucking hate it if people would find a way to start living in houses of under 20 thousand euro's. We'd be free. I'd love to be wrong and know people that would move to Lithuania if it's easy.
Basicly your frame carrying the roof has got to be super super strong. Like a box that could self support and would stand on it's own. I mean just the strong beams. The walls have to be connected to it and ideally not fall over. Hehe. I think a big thing is what consists the hill out of? Is it rock of mud with rock. Rock you can just render with sand / chalk cement with a natural pigment. But
water coming through the rock could be a problem. Then you need a drainage system and a wall in front of that wall and ventilation in the space between the wall and the rockwall. If it's all horrible loose stuff you'll have to work on keeping that in place, maybe even poor a reinforced slighly sloping cement retaining wall. (Yeah i know cement causes
CO2, but you not living a slave life working for the system will safe tons of it). Then still you could have condensation problems.
Anyway, i'll stop talking now and leave it up to all the experienced wofati builders to say something clever.
Hope this helps.