I have a nice shaft, straight, around 12.4-12.5 mm with a LONG ivory ferrule I am willing to part with. I know it fits my Schon just fine, and I am unsure if it will fit a Joss. The ferrule does have a small crack near the bottom of it, but it does not affect play whatsoever. This thing has a really long taper as well. Plays DANG good. The shaft is rather old and somewhat dirty. It is definately a players shaft, not meant for a collector.
I can let it go for $150 plus shipping if you are interested...I only shot with it 1 time myself.
I can send it to you upon payment, and you can see if it will fit your Joss, if not, then just send it back and I will refund you your money.
Shorty