After getting the parts matched, I discovered that the nose cone on the Harrier is wider at the fuselage joint than the F-18's, I was pondering how I would make the F-18 part match the Harrier's but then I thought, just make the harrier part match the F-18's.
There's a point on the both fuselage parts where they are the same width so I made a mark on both sides where this was, I then glued a portion of the Upper forward F-18 fuselage to where it should go and then glued the nose cone on. I then cut a diagonal cut from the top of the nose cone join line to the marks on the side of the fuselage (top pic). I then cut the Harrier parts to suit (second pic). What surprised the heck out of me, was the neatness of the join, there was practically no sanding what-so-ever to do after the parts were glued together. Third and forth pics are showing the results, and I've placed the canopy on so I could get a visual of it all. I've also glued a portion of the F-15 rear canopy fairing in place just behind the Harrier canopy, this will be the beginning of the top of the fuselage going back to the rear fuselage.