I am building 21' dia. Nubian domes. Think the shape of the large half of an egg. 4" thick blocks, fabric wrap with earth plaster inside. Probably 6"x6". I would really like a form which created the horz/vert angles but since I received the Aircrete "mortar" formula just using square cut blocks as shown by dome Gaia might work as well. My thought is that if I have the angles I would use less material. I will be documenting all of my procedure so anyone helping can benefit as well. I suppose it will end up being cost/benefit. I know there are some smart innovative souls in the forum. So throw out some ideas for all to tweak.