To decide which weight bamboo is best for you think about what you want the fabric to do for you. It is a balance between absorbency and drying time.

Absorbency Vs drying time
The heavy weight fabric is super absorbent, but it takes longer to dry, so it is great for night boosters where absorbency is most important. <p>

What are you making?
If you were making breast pads then it would be better for the fabric to dry while it was being worn, but the absorbency is not as much as in a nappy. <p>

What climate do you live in?
Think about how often you wash, and how long it takes to dry fabric in your climate. If you live in a hot dry climate you will have no trouble drying the heavy weight fabric. If you live in a cool or humid place you might be better to use more layers of a light weight fabric.

If you can’t decide, choose the mid weight fabric! It is a good multipurpose weight