:eek i'm liking that!
if i may (and not all will like this) lower the nacelles so from the front they are under the saucer.
edit1: actually do that then bring forward and aligned with the central part of the secondary hull. picture on way
as you can see in the picture the nacelles are about centre of the "y" axis which acording to my research should negate the need for the aft undercut allowing for more hull.