I used the tiniest size initially (the one for 4-9 lbs). Once DD was in her XS fab fitteds we used thirsties XS covers. The fab fitteds & the XS covers rubbed her cord area really bad at first so we were using KL0s w/ superbriter covers b/c KL0s have a niche for the cord area & super brites were a bit snugger & therefore lower.
I started the Super Brite in size small and found it to be cut a little bigger than the Super Whisper Wrap small....so I would assume the NB Super Brite would be cut a little bigger than the NB Super Whisper Wrap, but not as big as a Thirsties XS (I think the sized Thirsties covers have a LOT of extra fabric). I would guess the NB Super Brite would be a good size for the newborn fitteds/prefolds. I don't have any in this size, but I like them a lot. I would definitely try this cover for NB (and most of our NB fitteds are TFF), but we already have a ton of NB covers and I just don't need any more.
Re: Size question
DD1 born 5/24/10.
Missed M/C at 14 wks Feb 2012.
DD2 born 5/14/13.
Missed M/C at 9 wks July 2015.
I can't comment on the fit (still waiting) but I got my xs superbrites for 25% on labor day weekend at www.thenaturalbabycompany.com
There are other sites that I like to buy from, but this was the best deal I found at the time.
I started the Super Brite in size small and found it to be cut a little bigger than the Super Whisper Wrap small....so I would assume the NB Super Brite would be cut a little bigger than the NB Super Whisper Wrap, but not as big as a Thirsties XS (I think the sized Thirsties covers have a LOT of extra fabric). I would guess the NB Super Brite would be a good size for the newborn fitteds/prefolds. I don't have any in this size, but I like them a lot. I would definitely try this cover for NB (and most of our NB fitteds are TFF), but we already have a ton of NB covers and I just don't need any more.
Definitely get the NB size.