Gravity feeder and gravity waterer, these are one of my first designs made with Autodesk Fusion 360. They are designed to work with a 250ml slim can but you can scale up to fit a 330ml.
The gravity feeder works better if you make a bigger hole in the can. It is very simple tu use, just fill the can, put the feeder on and rotate it 180 degrees and let gravity do the work.
And for the waterer, just fill the can put the waterer and rotate it 180 degrees (make sure to use a can that has no holes in it).