Re: tuning Flat or sharp?
Stay with me now, when the guitar players tune their guitars down a half step from the keys they love to play in, probably A and E, this would put you in concert Ab and Eb. These are easier keys for most sax players. When they go back to the regular tuneings you are in harder keys. My suggestion would be learn that blues scale you talk about in all 12 keys. Then problem solved.