(1) Do you believe that the Journe designs, in particular the Octa RDM, will stand the test of time?
The Journe design with eccentric hour dial already looks a bit vintage. Something one could call "retro-futuristic" from H.G.Wells' "Time Machine" or as Bernard once pointed out to me the "R?gulateur" comic book by Corbeyran & Moreno. That said, what will make it stand the test of time is whether you like the design or not. I love it, and I can see myself wearing my Resonance in 10-20+ years. People's tastes change, but I think all of Journe's designs will still be interesting and wearable down the road.
(2) I know I shouldn't be asking this because I should be buying with my heart and not my head (and I will!), but what is the most versatile color combination of the Octa RDM?
I think this is something only you can decide. It depending on what you wear and your surroundings. Platinum may be better as a stealthy watch because it looks like steel. Rose gold is warmer. Regarding the dial, you can either get a matching dial or mix and match. I personally like the contrast of the dial and case a little more, but I would also be happy with matching dial and case. I was at my local dealer looking at a Calendrier in PT with WG dial and it looked great!
(3) Can anyone share any real pictures of the platinum, silver dial Octa RDM?
Unfortunately we only have the PT/YG and PG/WG combinations in our gallery, but if you look at some of the other models in PT/WG you should get an idea. There is no substitute for seeing and feeling the watch in your hand, especially a Journe, so I highly recommend going to a dealer to try them on.