Sorry for not keeping this up at the moment. Spending some vacation time in Europe, while some of the early prototypes are pumping their first couple of weeks to see how different solutions work out. I went back to the tilting action, but a little simpler, with a hose tie that locks the syringe and moves a little back and forth.
Regarding the priming, yes you would probably manually move the clock a few rotations until the solution starts trickling out of the hose. I am planning to use the "mini airlines" to reduce the amount of liquid stuck in the hose. Also, you would probably want to keep this close to the tank, and minimize the length of the hoses.
When I come back from vacations, I will update the thread and show some of the designs that worked better. Along with some clear instructions on how to Do It Yourself.