@saburrows You appear to be doing the right things....drinking lots of water to stay hydrated to help with the mucus and health in general.
You are nebulizing, you know about the huff cough,. Have you looked up the various ways of doing airway clearance like percussion, Autogenic Drainage, Active Cycle Breathing...all under the umbrella of Air Way Clearance Techniques.
Also, have you been diagnosed with Acid Reflux of any type. One must take that into consideration if trying postural drainage under the umbrella of airway clearance. The professionals don't recommend it if you have a type of acid reflux.
Personally if you could I would see if you could go to NJH in Denver, I know that might be difficult for a multiple of reasons. National Jewish Hospital/Clinic in Denver test you for a week long to see if there are any other types of problems that are associated with Bronchiectasis that might help knowing in this journey. They have concentrated on respiratory illnesses since the late 1800's.
Hope all that you have read on this site is helping somehow.
Barbara