rs1026, are you getting private lessons on the saxophone? If so, since your instructor can actually see you play, what does he say about this?
I read in one of your other threads that someone suggested just practicing for a while before you switch mouthpieces. I think this is a good suggestion - 1 year is not really that long of a time to establish your technique.
Also: you mentioned that that your high notes sound thin. How high are these notes? Are you describing the notes above high C# (the ones where you press the upper keys with your left palm)? Also, are these high notes in tune? (do you have a digital tuner?) If your high notes above C# are in tune, that's not such a bad place to be in after playing the sax for one year, even if they do sound thin.