I am guessing that you just have to play around until you find something that works (or until you adjust to the horn.) It seems that whenever I switch altos the new one plays out of tune compared to the current one. I have a number of altos including a couple of CJS, Yanis, MK VI, and an SML Rev D. I find that the CJS horns play more readily in tune than the other horns. I use an old Selmer Jazz F metal piece, a 60's Berg 85 1/m, and a Yani metal 7. Occasionally a Brancher J21. They all seem to work quite well for me. In fact, I like playing chromatic "exercises" on the CJS because the finer pitch distinction are so readily obtainable. As I recall, the B&S piece and a Meyer 7M also played nicely.
Just keep working with it. Good luck.
Just keep working with it. Good luck.