It also depends if you like to drink recreationally for hours, or just want to "get there" quickly with a couple of strong shells, Tanna style.
I drink for 4-5 hours and find a mix of 100g to 1250ml (about 40 ounces) to be good. My shell size is about 150ml (5 ounces). I might mix another liter with 50g after this, if not too much work on the next day.
30g to 8ounces will be strong but also probably not enough water to make an efficient mix