Forgot to mention I was pretty skeptical about measuring the tiny doses. For practice we squeezed out drops and counted how many from 1.0 to .5 mark, then .5 to empty, usually 4 drops = .5u. Logically .5 minus 2 drops would leave.25 but I could not see much of anything left in the barrel and syringe cone. So further practice, starting at .5, I squeezed out 2 drops then squirted that practice .25 dose onto wax paper where I see could what if anything came out, and how hard I had to push the plunger to get it all out. After practicing that a few times I got fairly consistent with how much was left in the syringe to shoot Jasper. I have calipers but I use both hands to control squeezing the drops out and decided drops counting is close enough. FWIW, I am still truly amazed such tiny doses have any effect, but the data speaks for itself.