Nice! The Blueprints Database at the Cygnus-X1 site should have a copy of the Spaceflight Chronology as i recall, down in the Tech Manuals section, but it has a chronology for the DY series with art by Rich Sternbach for 3 of them if you want references to work off of.
Either way you're off to a great start so far! I am looking forward to your progress and the design's evolution!
Thanks! Yes, I did end up looking at various designs. DY-500s and variants, 750s and many others. I decided on saying that this ship is a DY-550 variant. Also that that means that each ship has that as it's registry. DY-550, DY-551, DY-552, etc. This one being the Polaris, DY-551.
Don't let the details get in the way of your story. The real writers don't. Continuity doesn't matter...
Yeah, I decided to handwave any of those concerns here.
This is a great idea! And I agree with
@Shawnster - include what you want in your piece and work out the continuity later (I couldn't even begin to try and explain how all the characters and ships came together in my piece

).
Your DY500(ish) is looking good!
Thank you! Our story here is that the very first "Jupiter Station" is under construction. UES Polaris is loaded up with supplies and crew members for the station. En route, the time portal thingamabob opens up, and out pours the shattered debris of the Narada, and the Jellyfish.
This creates a problem. The wreckage contains humanoid remains that are very similar to Vulcans, and a second smaller ship (the Jellyfish) has markings identifying it as Vulcan. The Vulcans of 2079 want to take possession of the wreckage. But they are in United Earth space. Thus begins a difficult standoff with Vulcan authorities (who know from the markings and bio readings, that these are Romulans, but do not want UE govt authorities to know that).
Meanwhile, some factions on Earth that remain outside of UE government (and are responsible for those Courts we saw in Encounter at Farpoint) had agents aboard the Polaris. They are posing as Jupiter Station crew. But when the wreckage appears, their plan changes. It is soon apparent that the wreckage contains radically advanced technology. Far beyond even that of the 2079 Vulcans. Stealing that tech and sabotaging the Jupiter mission are their new priorities.