Stig,
Extracting the DPX-files with RedLogFilm / REDGamma3 (or 2 if you don’t have 3) is fine. It is pretty common practice for feature film and commercial work. Make sure you use “use meta from each shot / metadata as shot” to retain metadata used in the camera on the shooting day.
I tend not to use RMD / RSX data. Since we do not want to “bake” a look in to the ungraded DPX files.
(Yes I know that white balance, iso etc is tweakable metadata on R3D)
Good DOPs should have shot this correctly / well balanced.
A good safety precaution is to check that nothing “clips” in the histogram. If all the detail is retained, you should have all you need for grading.
I would not recommend pre-grading before VFX.
Most high-end VFX houses have LUTs for RedLogFilm, or at least RedLog.
The LUTs are only used for viewing while comping.
If you want to give the VFX artists some bearing on how the intended final grade will look. You can always make them a custom viewing-LUT so that they have better understanding on the “look”.
Basically when the finished vfx-comps come back the colorspace / gamma should be indenticle to the original “plate” you delivered.
Depending on how “heavy” the VFX are of course.
For typical rig-removal-shots the “plate” and “comp” should be exactly the same colorwise. If not, then usually the VFX Artist has exported with their viewing LUT still on.
Use RedCinexPro / Monkey Extract / Da Vinci for R3D to DPX extraction.
And you loose the ability to tweak “RED metadata” when going to DPX.
But this is not a problem!
There are many thoughts concerning how to this type of work, but this works fine for all the VFX-houses I’ve co-operated with over the years 8.)
—
// Dylan
Online Editor / Colourist
Nordisk Film ShortCut Norway
Showreel: http://www.dylanhopkin.com
IMDB: https://www.imdb.com/name/nm4104429/
Twitter: drhopkin