Nerites are great, but I agree they look like mysteries. I'm also a big snail fan.
Invertebrates are actually more sensitive than a lot of fish when it comes to water quality, so definitely check your nitrites and nitrates. Also, there's a chart (I'm on my phone, sorry)- Google kh co2 ph chart. You want to make sure that the minerals in the water are accessible for the snails. If all of your carbonate hardness is in dissolved CO2, the snails can't use it.
Cuttlebones are very good, but sometimes they develop a film that flakes off and is very unsightly. I take mine out when that film forms.
I feed my snails spinach sheet seaweed, but they also eat the flakes, shrimp pellets, and even blood worms I give the fish! Oh my goodness one time I gave them a carrot cut into two pieces. It vanished within minutes, but I found it days later *inside* one of the decorations. I've also started growing my own algae, but that endeavor is approximately two weeks old.
If you put light things in the tank, they will play with them. We got some of those clear plastic blobs kept by the betta stuff, and I swear they play catch.