If you have it as a single obj you can edit the UV's in Carrara by hand...pull them out along the top and bottom where they are piling up. It's a pain, but... Can also wait for Hexagon 2 to ship, as it has both seam tools and a "relax" function that should make fixing a UV map much easier. I dunno about the whole assemblage thing. I just tend to work on a vertex object and weld parts in. Is more wrangling of vertices, tho (probably why I get so little finished).