I am curious when one should know that just the right amount of water has been added? I worry about having to dry of a cream and also worry about a runny cream. So when is just right?
Rub some lather between your thumb and forefinger. When it's slick with just a little sticky "give" for cushion, that's a good place to start. You might want to go a little dry or wet from there, but that's a good middle ground.
If you truly have lost 1/4 of the hairs (meaning you're not exaggerating) take it back. That's neither normal, nor acceptable for any brush.I've already lost about 1/4 of the hairs from it
This is very subjective.
English and German creams can take a lot of water. Other creams seem to take very little.