What is the best way to store opened bags of coffee beans? In general terms, the best way to store coffee is in an air-tight container, in a cool, dry and dark place. A cupboard in your kitchen is ideal.
Your cafe should be making a healthy profit on its coffee sales. A 20g basket is plenty to make two espresso's with quality coffee. There is no need for +30g - this will eat into a cafe's profits and only benefits the roaster. Do your numbers - you might be surprised.