Hell, I'm only a recent convert to live view (IMO, the implementation on the D700 was a little clumsy; the D800's a lot better!) let alone focussing using it!
Personally, given Stewart's available hardware, I would use the longest zoom I had in stock coupled to the highest pixel density body I could beg/borrow/steal, possibly in front of a telecom, the rig mounted on a good gimbal head. I would pick up the ISS at the shorter end then track it and zoom in. It's a bright enough target for AF to lock onto (hell, even my bridge managed that task once I'd got it in the cross hairs!) so I would trust that to do that part of the job. Since a full overhead pass is up to about 4 minutes long, I would keep shooting and praying (yup, good old machine gunning!). I would be in M mode and I reckon 1/1000th @ f/8 should be a decent compromise between freezing the inevitable shakes (both subject and camera) and diffraction softness and an ISO to suit. If the weather was playing ball, I would use one pass (or part of it) as a test run to ensure the optimal exposure.
However, given my more limited kit, I'll probably just set up a film body (if I remember where the RFs are!) with the widest lens on, loaded with 400 print film and leave the shutter open for the full pass! TBH, I might even hope a few planes go overhead during the pass - IMO they add some interest to a star field with a streak across it! After all, I'm not a pro so any images I produce only have to please ME!!!
