Actually, having a neck at all seems like a rather significant departure from the template. It looks to me like the saucer sits right on top of the secondary hull, almost like on Voyager.
As far as using a neck goes, I must say the one you currently have is way too thick either way. On a more fluently shaped design it might work, but not here, I'm sorry. The rest, however, seems like a solid start.
Really? I honestly see a short and thick "neck" in the vast majority of panels in the comic! I guess that's the thing about working from these vague sketchy references heheheh; everybody is going to see something different.
To anybody who has a different interpretation - please feel free to post a sketch or image manipulation of what I've posted or whatever showing what you're thinking! In the meantime whenever I get a chance I'll try to come up with some refinements to the "neck" area.