Re: help with low notes on bari saxes
I found it helpful to make sure my Bari Sax reed was moist and ready, moreso than alto or soprano. Also, you need to open your embouchure more for the bigger mouthpiece, more mouthpiece in your mouth. It might feel like you're eating it for a while, but you'll get used to it.
(Of course you know the drill: practice, practice, practice!)
Hope that helps!