I cannot buy syringes with needles in the USA without a prescription from a Doctor. Besides, using the hand held syringe makes it difficult to accurately ramp up the flow rate. And, this must be done with 2 solutions, Silver and Salt. I did try a syringe with a plastic "needle" for backpressure, but I could not get the flow rate down low enough, nor hold it constant enough, nor ramp it well enough.
Believe me, using a syringe of some sort was one route I explored, along with several dummy water rehearsals to fine tune my technique using several methods.