To get the dome exactly like planned I constructed the two identical faces in CAD and printed them on 4 A4 pieces of paper, glued them onto some 18mm thick spruce planks and cut them out with a jigsaw:

I then screwed wooden slats to both faces to create some kind of trough:

This mould fits perfectly this time. You can see the shitty one in the lower right corner. It got destroyed later and used as fire wood :)

There's only one good method to in-cooperate all the ingredients thoroughly: stomping it like there's no tomorrow:

This time the ratio was much better. We used chicken wire to give it some additional strength:
The mix was still quite rich but worked perfectly:

This is the result of a few hours stomping on mud like crazy and slapping it against the soon-to-be oven to create a nice dome:

Here you can see how the drum sits on the frame. The two (not painted) bars can rotate by a few degree.

That's it for part five of this series. Stay tuned for the fiery part six. What do you think is the best way to remove the wooden form? :)