This guide tells you how many canisters you should have throughout the level when doing all challenges. There is also some help on some of the more confusing levels of where the canisters are located:

https://docs.google.com/document/d/1dU1MKifOSwtG-bHHC9mvCk1yvTuiRthqJQFkeac8PGI/edit?usp=sharing