Sorry for resurrecting a somewhat old thread. I've been on a forum hiatus for a while.
Cineform is a very high-quality codec, however, the workflow to properly transcode your source clips requires the use of Compressor.
There was a project at the university campus here a while back that encountered a similar issue. One of my co-workers works on a camera that uses the Cineform codec, and he confirmed this workflow. The idea here is to transcode your source media to ProRes, and "Reconnect" it in FCP.
You will need to do the following:
1. Locate your source media via the Finder.
2. Create a separate folder with a similar name to that of the folder which contains your source media.
3. Open Compressor.
4. Add your Cineform clips to the Job window, and apply the appropriate ProRes setting. Set your Destination to the secondary folder.
** I would recommend creating a "Custom Destination" for this. By using a Custom Destination, it will automatically strip away the preset info from the exported file name. The idea here is to create new source media using the same filenames as your Cineform media.
5. Submit your batch.
6. When the transcoding has completed, go back to your FCP project and DUPLICATE your sequence (for backup purposes).
7. Select the clips on your timeline and take that media offline.
8. With all of the clips still selected, reconnect them to the new ProRes clips. (This is why it's important to keep the filenames the same.)
9. You may need to change the Sequence settings to match your ProRes settings.
10. Send to Color.
Hope this helps.