Hello Mark,
fascinating project, well done!
I think the biggest problem is to concentrate yourselve for every photograph taken and allways have enough overlap. Do you have to reshoot some segments because of lost alignement, gapes?
What do you think of the new fisheye support of PhotoScan would you use it for such a project?
What have you done with the texture, because I think even a 16k texture is not enough for such a large project?
Karsten