Rune Felix Holm

Then I don't understand your question. Is there a better way to key log material?

When you key in rec709 color space keying becomes a lot easier and more precise in a rec 709 project as mentioned in the original post from Thomas.

Pipe the mask output from the rec 709 node to your log nodes to stay in log all the way to the lut. Stefans image shows how to set this up. All that is missing is to connect the key matte output to the log grading nodes.

A colorspace aware qualifier would be the best solution. It would make sense to suggest it to BMD on the BMD forum. As far as I know there is no simple solution other that keying in the timeline colorspace via a cst node.

Will the looks be ready for HDR grading and delivery?

The v17 roto module is impressive for what it promises to be in the future, but for now it is no more than a first attempt and I haven't been able to use its output for anything meaningful yet.

You could consider outsourcing the rotoscoping to a company that specializes in roto and then do the rest yourself. Really good roto is really hard and takes years of practice.