Some of us cannot tolerate 7% or even 3%. I was started on 7% when I was first diagnosed with bronchiectasis in 2011. I used it twice a day for years without any problem. But eventually I could not use it. I would inhale nebulized 7% and immediately start coughing. After 5-10 minutes the coughing would finally slow and I would try inhaling the 7% again but the coughing would start again. I had to stop using it.

When I changed pulmonologists in 2018, my new doctor prescribed 3%. Although I coughed a lot I was able to use it for a year or two but then the bad coughing started right after the first inhale and continued just like the 7% and I stopped.
Last year, Dr McShane who has treated my bronchiectasis. MAC and other organisms, sent me an article about the efficacy of .9% in moving sputum out and I have been able to use it.

I believe that I have trouble with saline because I have a lot of inflammation. I have chronic bronchitis in addition to bronchiectasis and my lungs are very fragile and absolutely do not want any salt on them.

We are all different and you may be ok with 7%. If not maybe you can use 3%. But if your lungs will not tolerate either of these, then .9% will help get the sputum out although it will not kill any bacteria.