Hello Mark, have you contacted any of the post-Covid programs in the area?They usually include a pulmonologist who may have some insight for you. There is a Center at National Jewish Health in Denver, where they have a world-class pulmonology department.

As for masks, part of the cost of N-95 masks is that they are sized, and you need to be fitted for it to be effective.

Instead I buy certified KN-95 masks, when I am at my desk tomorrow I will post a link of those which have passed inspection. They are about 1/3 to 1/2 as expensive, and nearly as effective. A few weeks ago I was wearing them 9 hours a day caring for sick kids, and didn't catch my young grandsons' contagious respiratory virus or strep throat. I wear them everywhere.
Sue