Keep it simple to start! (KISS)
Bass Tackle Dual Injector with blending block.
Unless your doing a LOT of baits and need to go to one of the "production models" discussed.
Personally, I still like using laminate plates (or hand pour the belly) the best for most of my baits. The Dual Injector is more fuss that I need most of the time! I always seem to be at least one hand short whenever I'm using it!
And...I do like having two nice injectors!
Andy