The syringe is the way to go. I use HC110 as well, and it was a real pain until I got one.
As for the powder fixer, definitely mix it in a separate container. Don't dump it in all at once, add it slowly while stirring. On second thought, why use powdered fixer at all? Kodak (or Ilford) Rapid Fixer is easier to mix, doesn't have to be made all at once, and it's faster, which really helps when working with TMAX films.