I just bought a RS and I'm having a little trouble getting my DS (2wks) positioned correctly. He's not big on being tucked into it in an upright position while awake. I can't get him and the sling correctly positioned for a cradle hold. His head ends up either tucked into his chin or very close. Also, when in the cradle hold, should he be laying on his back or on his side? His little body seems twisted when lying on his back.
I'm not sure how to properly tighten it, either. When it seems tight enough, he's pretty well smushed into me and the sling digs into my neck. But when its not that tight, it seems too loose. It could be that I'm just not used to the sling, I guess??
The best thing would be to find a babywearing group nearby or someone who can come and show you how to do different positions.
Also, I would go to thebabywearer.com for a ton of info. There is an entire section just on slings in the forum.
DD only liked the upright position with her feet out, no cradle or froggie legs! Cradle position makes me nervous anyway.