Looking over the picture after they posted, I would like to draw attention to the window framing. #1 & 3 used ordinary framing and the windows were high where they do not have a heavy load bearing. But #2 has the recommended framing using the same logs, in this case mitered on the corners. I think it would be stronger with a but joint between the verticals and horizontals and narrower if carrying an earth
berm.
I remember watching a retired carpenter build one by himself. The bottom of the logs was notched to fit on a 2x4 bolted the the foundation wall. The corner log was flattened on two sides at right angles to each other with a groove in the center of the flat side. with the corner braced plumb he drove a spline into each groove then he could put the bottom of the next log against the footing and stand it up with a brace and pound its grove into first spline add another spline and repeat on each side.
With the shiplap log that I am advocating it
should be easier and require less pounding and the logs could be tied together with 2 long screws trough the lap. Using a sill log with a lap on the top facing outward on a drained gravel foundation the pressure of the berm would be transferred to the earth floor on the inside. A header log could be notched the same with the ceiling logs lapping into it. For the arched portions I think ti would be good to have each horizontal log notched into its corresponding vertical log.
I will have to go back to Sketchup and see if I can make the structural elements and assemble them. also I would like to do the
greenhouse berm and roof patio design which would incorporate a
rocket mass heater/cook stove on the outside that could heat a sleeping bench on the inside. Perhaps a rocket mass
water heater/cook stove like in 0.7 that could also heat a sleeping bench on the other end.