One material that I like very much to work with is the CDC. On the market you’ll find a lot of tools that help you work with Cul de Canard feathers. I worked with a lot of models and types: PetitJean clips, paper clips,foam blocks etc. but the best seems to be the Vosseler Xpert Tool Clip. I tried this tool right after visiting a fishing exposition. I saw this tool in the hands of a great German fly tier. He used it very easy, fast and without wasting material.
The tool has 3 grip levels
Fixing the feathers
Cutting the barbs
Grip down the barbs
Forming a hackle loop:
Working with marabou:
Working with deer hair:
Here you can see a very good grip even for a lot of hair: