Dude: look at a visine bottle. It says 16.4mL. So take a bit out and it's 15mL.
Fill it up with water and then use that quantity of water to dissolve the pills in.
Yes it works with the ER.
Just go to a pharmacy and ask for an oral syringe or one with a spray nozzle.
The alternative is to find a tiny funnel from a cooking set and put a small (1/4 of a cotton ball) in the bottom of the funnel, press it down, pour the liquid over it, then squeeze the visine bottle to create a vacuum to suck the fluid through the filter (out the bottom of the funnel)
milligrams and milliliters are pretty easy to measure.