The girl I am seeing currently is a very big squirter. She didn't start to squirt until she met me though. I kind of turned on her "faucet" The best way for her to do this is to ride on top. How much depends on alot of things, but it soaks a doubled up beach towel everytime.
As for your second part, "Golden Showers" are fun, but not for everyone. Your girl must be very comfortable with you to do this intimate activity.