I have the same or very similar eyedroppers, but I cannot tell you specific amounts. I think using ratios instead.
A common "rule of thumb" says to thin till your paint looks as thin as skim milk. For me, the problem is that I don't drink skim milk, so that doesn't help. But I'll thin my Tamiya X/XF acrylics starting at about 10:1 paint to thinner, and eyeball it, up to just less than 2:1, or 50%. I'll add that I'll use an eyedropper to measure the paint into the cup, too. That's about as precise as I get with it, though.
I don't know if that helps, but I hope so.
A PS...
I use the eyedropper to add water as necessary to my wet palette, too. I could pour water into it, from a bottle or a plastic cup (I use the plastic cups from chocolate pudding on my bench), but it's too easy to pour too much at once, or spill it. The eyedropper practically eliminates spills or adding to much water.