2K Cineon to SD video color space conversion with LUT and Combustion

This seems relatively straightforward, but continues to elude me. I have 2K media in Cineon 10bit log 23.98. Now, as the cineon files were graded for film output on an ArriLaser, I need to convert them to video color space in order to be able to output my video masters. I figured I should use a simple straight LUT in Combustion and then add an NTSC filter over the whole thing, before going through a full grading pass. Does this seem correct? So far, I've been unable to find a setting that is good enough as a starting point.

Any ideas would be appreciated.

Log2lin 1D LUT shows up as way too dark on most of the sequence. I figure it's a ref white or black issue, but adjusting those arbitrarily seems a bit too ballpark. Since the Cineon stream is fully graded, I am trying to avoid having to do another full grading pass on the whole thing. Is there a relatively straightforward "scientific" method of bringing the clipped whites and blacks back in?