I made a wasabi ginger ale and used 3oz at 30 min, 1 oz at 10 min, 1 oz in secondary. That was for a 2.5 gallon batch. It has a nice Ginger aroma and a slight ginger flavor. Could use more in the secondary or at the end of the boil to get more ginger to come through. As far as the coriander I wouldn't go over 1 oz for a 5 gallon batch at the end of the boil..
Toasting Tortoise Brewery
Primary - Slightly Smoked APA V.2, Milk Chocolate Oatmeal Coffee Stout
Secondary - American BarleyWine.
Kegged- Indian Brittish Ale,
Dry Irish stout.
Bottled - Rum Oaked Porter , Hibiscus Mead, Belgian Pale.