I have a ring sling and a moby wrap, I haven't used either yet. (I also have a Becco, if that's the best)
What is the safest way for baby to nap in a carrier? I'm experimenting right now, but I'm so scared I'm gonna do something wrong, and she's gonna stop breathing!
Also, "back is best" but if I sling baby onto my chest, can I sleep sitting up (she's semi-face down/vertical)?
Safest is always upright tummy to tummy with baby high and tight on your chest. If you are asking if you can sleep with baby wrapped on you...no...I would not. I have lots of Babywearing info in my siggy link that might help.
Re: what is the safest way?
Breastfeeding Counselor with Breastfeeding USA
Babywearing Guide ** Newborn Carriers
Cloth Diaper Guide
Safe Bed Sharing Info