I've had GREAT luck doing this kind of thing using Danny's UV tool melscripts!

VERY easy to use, and FAST too.

The idea is to select orthographic views of your geometry, and assigning shaders and projections to those sections of faces.

Then, in the uv editor window, watch the layout magic of his toolset happen automagicly

Then, all you gotta do is sew the sections together with minimal tweaking

Try the tools out here:
https://forums.simplymaya.com/showthr...&threadid=3719