Wow! I feel much better now about using sodium chloride, but this its really strange the CF services pharmacist (I spoke directly with a pharmacist) said its "unusual" to do it that way versus with sterile water.
I've always mixed with 2 mL of either sterile water or sodium chloride. Coli makes me cough, but I get more up that way, so I thought that was a good thing if its kinda irritating while I do it.
Thanks, everyone!