well i don't know anything about the 730 really except i've seen it in a few chronos. seems to be a triple date, full chrono, manual wind setup from what i've gathered. i have no idea if it's number is really the 730 only, that i have seen or if it's part of the 73xx family you mentioned??

i haven't been able to find much on it, so if anyone has any insight..please expand..it would be greatly appreciated and thanks in advance, of course.

j.h.