I would do only CWE on powder.

As soon as there are fiber pieces I would opt for boiling to get better into the material.

Of course you can do CWE on finery shredded but you need more time.

Just as you can boil powder, then just 15 - 20 minutes is already enough, 1 wash and there you go.

For boiling and CWE I used to work with pH 3 water phosphoric acid.

Boiling, to me, was less bad taste. YMMV.

Hope this helps, happy trials.