This seems like a nice thread to weigh in on.
It is certainly NICE if you create your own announcement in the appropriate thread (True Fanedit or Extended Editoin). When you create it yourself, you are in complete control of how the edit is presented that first time out the gate, at least in terms of the Forum side. The only thing I would recommend is that you time it for when you actually submit everything for your edit, the form information and links for all needed elements including artwork. This makes the job of posting your edit a lot easier for us (me) and gives you full and complete control over the presentation (no having to go back and edit what I write up for you).
One word of advice if you go this route (not using an in-the-works thread prior to your release), make a big splash when you announce it. As you won't have the benefit of building a buzz or anticipation that an ITW thread can generate for you, if you want to grab people make that page sell your edit. Using pictures is always good, but also, be very clear in what the edit is, what sets it apart and why people should be interested, a trailer would be particularly helpful.
Good luck! (and your badge has been assigned).