you have to try it out,
tea might vary from year to year, might be some left overs, might be some forgotten somewhere and repackaged etc etc
thus yield a different cup with the "same" tea.
once you know the taste, vary things around so you see what you like better: more/less leaf, more/less time, temps etc
i usually start a black tea with a "tablespoon" (eye'd) then 4oz 200F water 3-4 minutes. sometimes i want it stronger so i add more leaf. i usually also let it longer to see if any nasty tastes come around (one of them i call it "teabag astringency")
a good yunnan gold will not go "bitter" or unpleasantly astringent.