Yeast wise, I'm solely a dry yeast user so far. I use one pack on 2.5 gallon and 5 gallon batches and don't notice a difference there so I doubt it's under-pitching as a primary issue. My most used yeast is nottingham, so it shouldn't be a flocculation issue.
With the BrewBrite, that can't go bad can it? I've got some from the early 90's that I can get for free.