One bottle per cage here too
I keep an eye on the bottles and make sure they are working. When I've refilled each bottle I give it a shake (spout down) in case any air is trapped. If I get water on the floor then that's good! I use the 'classic' bottles as I've experienced least random failure with those (excluding when hamsters push their substrate into the spout overnight). I wanted to move to glass bottles for ease of cleaning but all of those jammed without warning so plastic it is for me.