When did your NB diapers start fitting? DD was 5lb 13oz at birth and is now back to that weight, but most of the diapers are still too big- especially around her legs. My Sposoeasy's are pretty good, but BG XS seem huge and we can't get a great fit with GMD workhorses... I have yet to try my prefolds with Thirsties XS covers.
Will we be able to start using cloth soon?? I hate disposables
Re: For those who had tiny babies
We'll miss you sweet Debbie Girl (4.21.12) and sweet Cindy Girl (8.9.12)

Ours are velcro for this reason. I guess I'll give them a try!!
I ended up having to start my DS in premie sized prowraps and newborn prefolds (he was full term, just small). Worked great. I can't remember how long it took him to be able to fit the newborn CD's though, sorry.
If I were you, I'd go ahead and try your prefolds and xs thirsties. As long as you can get a good fit around the legs and waist, you should be good, even if they seem bulky.
GL
DD was 5lb 14 oz when we left the hospital. We used sposies for probably the first 2 months. Then the pockets.
PF's with covers (Thirsties DUO XS and size 1, Flip and Grovia) fir much sooner but we prefered pockets.
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At 5 lbs the preemie prefolds and Thirsties XS covers fit, though they were ginormous. Then we moved to GMD orange and Thirsties Duo 1s or Proraps.
And congrats!