Hi
We are recent converts to water bottles as well, and I had the same concern. Just need to monitor how much water is disappearing each day, and the floating turtle inside them makes it pretty easy. PLUS, watch him as he drinks and watch the water. If you see bubbles coming up in the bottle of water, then he's getting water.
I bought the Lixit with the flat back and quick release lever. I was able to mount one on the kitchen wall by using only the one part of the bracket, and the other is on their xpen for night time. I also mounted one on the wall on the porch so when we're outside they have water too
It might take him a day or two to adjust to the bottle, but as long as he's peeing, he's getting enough
