For the G9 at ISO 800, Thomas Niemann (of PTLens fame) has suggested the following settings in ACR Details page:
radius = 0.8
detail = 30
masking = 0
luminance = 80
color = 100
I tried these settings on some G9 pix at ISO 800 and was disappointed at the apparent loss of detail despite some ugly luminance noise artifacts sneaking through. I have used Neat Image and Noise Ninja, and currently use only Noise Ninja. If anybody is interested, here is what I did:
1) No sharpening (all set to 0).
2) No Luminance or Color Noise reduction (all set to 0).
3) Basic tab used to set optimal tone and color.
Converted at that point (16bit Tiff in Prophoto RGB)
1) Did an autoprofile of the image.
2) Inspected auto selections and added a couple of them, deleted one (It included some detail).
3) Did another autoprofile, with the improved selections.
Used the following settings in Filter:
1) Strength = 9
2) Smooth = 6
3) Contrast = 13
4) USM Amount = 50
5) USM Radius = 0.4
6) Turbo box was Checked
Strength = 12
Smooth = 10
Contrast = 10
Some noise was still visible in shadow areas, but it was minimal.
Detail seemed close to the original.
Viewing was done at 200% when adjusting the Filter settings, then 100% before applying Noise Ninja. I have to try some more images at those settings, then save them as a preset in Noise Ninja. Then I will tackle other ISO's.