The amount in each "drop" is going to differ depending on the density... that's why I think they say to use twice as much ECA, because it's much heavier, so the drops will be smaller.
The one that's clogged on me is Green Gain. Again I just work around it... I tried widening the hole with a pin but it's just easier to use a dropper. As I said in the topic it's only a small gripe.
ECA is 2 drops per 5 liters, Phyton Git and Green Gain is 1 drop per 5 liters, and Green Bacter is 1 drop per 10 liters.
Not sure if I can attest to how well they work yet... I haven't been using them for that long.