So you only apply the lens profile module (300 + ext 2.x) in DxO for those photos? Nothing else?
Personally, I often apply a variety of corrections in DxO – exposure, WB, vibrance, level and crop, etc. However, with the exception of dust removal all of DxO's tools are global. For local edits, I use CS6.
Same here, and there's no profile for the 300 f/2.8 IS II with or without extenders - hopefully someday, but the (auto-)corrections would be fairly minor - a bit of vignetting, a tiny bit of CA with the extenders. The automatic sharpening with the lens profiles in DxO is really nice, however, and that would save me a lot of time tweaking the unsharp mask settings.
EOS 1D X, 5DIII, M + EF 24 f/1.4II, 50 f/1.2, 85 f/1.2II, 300 f/2.8 IS II || 16-35 f/4 IS, 24-70 f/2.8II, 70-200 f/2.8II || TS-E 17 f/4, 24 f/3.5II || M 22 f/2, 18-55 f/3.5-5.6 IS || 1.4x III, 2x III