As to those nacelles, the ship exterior was designed by Rick Sternbach. He shows up on the board occasionally. Maybe you should ask him.
The producers wanted something
on the ship to articulate. I offered up sketches of flaps on the nacelles, radiators, loading ramps, etc., and in the end they settled on the pivoting pylons. I just drew the plans and told the folks at Tony Meininger's shop to do what they could. Most of the bending shots ended up being CG, IIRC, as the motor/gear bits complained.