9 tiers up and the dome still hasn't started to dome. I used the arch chain and the radius chain streched them tight and found that the dome doesn't really start to curve inwards until 2 tiers up.
I stood the door frame upright and moved it until the arch chain intersected the top of the door frame and found that I had 1 bag length extra inside the living space, but thats ok - much better than having no bags to support the door. Going to have to get the assembly more level before reaching loft level.
To be continued....