Since you have the capacity, no reason to share a single EVSE. I'd say go with a pair of 50A circuits. That will allow up to 40A EVSE on each, which is a good rate that should serve you quite well.
I assume you will be using an electrician. Make sure to have him do load calculations with the EVSE loads in mind and whatever other loads prompted you to install a 200A service to the garage.
Placement is an interesting question as not all vehicles have the charge port in the same location. You want something that will accommodate various locations while minimizing tripping hazards. I initially looked into a ceiling mount with some sort of retractable spool, but while this is possible, it's VERY expensive kit. Great care must be taken in any sort of coiling arrangement, as it's easy to catastrophically overheat the wiring if too closely coiled. Probably the best I can offer is to get wall-mounted EVSE with nice long cables that can reach any point on the vehicles, maybe even extend past the door to charge a visitor's vehicle in the driveway.
One thing I've found very useful to mitigate trip-hazard is to wrap the (typically black) cable with a spiral of bright electrical tape. This is highly visible. I think it may have something to do with the way our brains are wired to be wary of snakes. I was concerned at first that electrical tape would get messy but it's held up quite well in our garage. There are also plastic "cable wraps" that would serve the same purpose but be more durable in high-wear environments and protect the cables from abrasion.