Aquilasax is great, excellent service etc. etc.
The middle C is fairly common I'm afraid, but using the ballad C isn't that big a deal. as for the Stack, could be a pad angle problem.
Ultimately, saxophones are never going to play in tune. These were made 80 years ago, so it isn't surprising that a little bit of creativity is needed. There are ways to compensate, including mouthpieces, reeds necks etc. etc. etc. I'm sure others more knowledgeable than I will help. Doc Frazier alters the angle that the pads make with the hole when closed, which is supposed to help with intonation.
The middle C is fairly common I'm afraid, but using the ballad C isn't that big a deal. as for the Stack, could be a pad angle problem.
Ultimately, saxophones are never going to play in tune. These were made 80 years ago, so it isn't surprising that a little bit of creativity is needed. There are ways to compensate, including mouthpieces, reeds necks etc. etc. etc. I'm sure others more knowledgeable than I will help. Doc Frazier alters the angle that the pads make with the hole when closed, which is supposed to help with intonation.