Hi Ed
Thanks for helping with this. I cant understand why I can get a smooth surface if I loft everything but get a lot of bumps and tears when I don't. Sometimes in Carrara I have found the vertices don't line up and that causes a black line when rendered. I don't think this is happening in this case as this is all one smooth object except where I have blended the windows. Both Carrara and Daz have smoothing options that make things worse rather than better.

I used the same output settings that you posted. At first I thought it might be because I selected too too few polygons.