Nothing is too citical in this design. as long as the diffed circle is the same as the diameter of the bottle and the thickness of the bars of the cage are about correct, it will work.
I supplied my OpenScad file - so you can adapt it to your own bottle.
The Bottle came with a silly wire tie, that was not going to last being twisted and untwisted every time the bottle needed filling, and with only one support point, the bottle slanted to the side as our rabbit was drinking... This quick and dirty solution solved the problem.
Printed in green PLA, because that is what was in the printer at the time. I bought a lot of it cheap....so for prototypes it's perfect.
- PLA or PETG
So simple is it
10 mins with OpenScad and we had it ready to print. Printing took about 34 mins for each bracket.
Prints well at 0.30 (my lowest res) and aesthetics were also part of the design, the raised supports make it look better, but also provide some extra support for the weight of the bottle.
Daughter - happy, Bunny Rabbit - Happy, so everyone is happy with this build, hope you are too.