Hello Sakoman,
Joe Lozito's website has been down for some time due to I understand on going medical problems. He's an old man and works slowly when he is working. A Forum member has a Zischang rifle with him for fitting Joe's copy DST's. The original Zischang triggers were missing when he acquired it and Joe had a set already made so you might think it wouldn't take long to drop them in and maybe do a very small bit of inletting. As far as I am aware the work hasn't been done yet and he's had the rifle in his shop two years. The original time quoted to do the work was a couple of weeks.
Harry