Matthew in your list of setups you didn't list a 987 setup for Caymans. A 997 19'' rear wheel (OE dimensions) is 19x11 ET 67, and for an 11'' wheel to fit the Cayman you need 19x11 ET 37 to fit a stock suspension and ET40 to fit smaller coil-overs.
Will an actual 987 fitment be made? Or will spacers be provided to adapt the 997 fitment to the Cayman? Spacers are a much less desirable option, as 11'' wheel really limits us to which tires can be used; preferably you should have a rear wheel between 9.5 to 10.5'' for the Cayman.