Well Wolfsglen, for your plan on making a top-mounted design I can offer my suggestions if you'll have them:
Split the yellow->red grill in the middle wide enough to accomodate the center pylon.
Reduce the depth of the pylon somewhat, and make it just high enough to clear the deckhouse and the diagonal boxes on the sides.
That would make the nacelle come out of the main enginering section, yet be backed up enough to work in tandem with the two mains...
That't be my $0.02...