My Ds was born at 31 weeks. I never did announcements with him and in hindsite I wish I would have (we did with my term daughter). But like the others I was so busy before and after he came home I never did.
But if I could do it over, I would have waited until he was discharged and done an announcement with a picture from when he was first born- with that birth info and a picture from when he went home with that weight and length too. Both dates and information are special to me, so I would want both on there. My only advice is do what you want on the announcement, not what you think othersd may want because at the end of the day very few people keep that stuff- but you'll hold onto it forever.
Congratulations on your girls! I'm so glad there is an end in sight to your long NICU stay!