We like to use House Again's tea infuser with Not Neutral Gino Servers to brew large quantities of tea for friends or extra servings for yourself.
Depending on the tea, we use 9-12 grams of tea to 600 grams of water and brew for 3 minutes. Although we can't cover the exact temperature you'll need for every tea here, using this as a general rule will help you: Generally, light teas require 175F - 185F and dark teas require 195F-205F. Herbal teas can be brewed at 205F.
To brew with House Again's tea infuser we recommend getting Not Neutral's Gino Server. We also recommend the Hario Scale or Acai Pearl Scale to weigh your tea and water.