Hey Dude

panic not!

Im probably one of the few who love doing the whole uv layout thing.

I used a cylindrical projection for the main engine with the seam hidden away underneath, but I think I still managed to get rid of that anyway. All the other circular parts were planar mapped along the z or x axis. if you want the uvs straight, select a row and use the scale tool to line them up, easy, same as lining up verts on a model.

layout wise I would go with the most optimum set of uvs, meaning the ones which cover the uv space the best utilising the whole area. I have days where its all a bit of a fuss with getting them right but if you have to split it into sections to make the uv set clean then do it, I can understand being precious about it all as Im a real f***** for that kind of thing, it has to be right, but somedays you have to bite the bullet and make do with it as it is.

Jay