Calibrating tea dosage How can I get the right strength of tea?

I recently have been trying Gyokura Imperial, a Japanese tea, experimentally, but it is hard to know whether I have the dosage correct because I don't know what it's supposed to taste like.

I guess if I had a color card maybe, but it would have to be for this particular type of tea, which has a somewhat yellowish color.
O-Cha.com says that a good ratio is 1g of tea leaves to 30g (i.e. 30mL) of water. 

Also keep in mind that, since Gyokuro is such a delicate tea, you want to brew with water that's between 120º and 140º F (50º to 60º C). This is much, much lower than regular black or green teas.