I think that if you polled 100 people here about their airway clearance process, you would get at least 50 different answers.
Are you still having issues clearing your airways? Do you use the vest while you nebulize?

My best trick (I don't use a vest) is to use my inhaler & nebulize saline first, do some activity - exercise, yoga, PT, housework or weeding - for 15-30 minutes, then clear my lungs.

Dr Pamela McShane suggested the "pause" between nebulizing and clearance to allow the solution to penetrate throughout the lungs and help to loosen mucus. She also suggests exercise to further move things.