When I ordered my car it was only available in the R-Design however I have since seen that it is available in both R-Design and Inscription models...
If I was in your boat I would probably go for the Inscription because the R-Design has such lengthy delays, unless you're looking at a blue or red car then you're limited to R-Design.
Apart from that there's barely anything in it.
Inscription gets chrome detailing, R-Design gets black.
Inscription gets full leather + electric passenger seat, R-Design gets part leather and manual passenger seat.
Inscription has a powered tailgate, R-Design has manual.
And that's pretty much it.