I made test cob using long pine needles. It works, but not nearly as good as fermented clay and straw. It's really more springy and doesn't always stay in the shap it was placed. I think it needs chopping into shirter length. I will quality these statements with this.. I have never built a full structure using pine needles. I have also used them in test forms packed with clay slip and pine needles.

Building a roof this way is material intensive. Next time I'm going to try a living roof. Seems like it would not be damaged by hail. In theory a vynal loner would last indefinitely...

It seems like a good idea to place a French drain at the edges to drain away excess moisture while holding fair amount of soil close to the edge

One thing we learned in the desert is that many places have high silt content and the walls and block fall apart after a year. If you run into this just know it can be fixed using water and gravity to separate the sand/rock, silt, and clay.