RE: B-17 Engine nacelle position
Now that everything is lined up, you can tack glue the nacelle patterns in place with some CA, and the rest of the process can be done normally, because the alignment is insured.
This is a pain... Much easier when the designer simply does all this for you and gives you precise patterns to use. But it works. I did all the steps above in a little over an hour, once I figured out how I was going to do it.