Hi Rob,
Please ignore the warning. When you get the V9 update, that warning will go away.
For the rMBP, you need to do a couple of things for now:
1. Switch off the option to “Automatically switch graphics” in the Energy Saver (as CUDA won’t work otherwise always)
2. Set the display scaling to 1440×900, and then back to 1920×1200 before you start Resolve (you need to do this if you get out of memory errors)
Regards,
Rohit