Snails are relatively easy, RTR wrote a couple of great articles, but I can't find them anymore to link them Maybe he'll see this and find them for us. The major question is what type of snails? The smaller guys like pond snails, MTS's and red ramshorns will breed with or without a partner, will eat any waste or algea that shows up in the tank, and will reproduce to the level of the food supply they are plant friendly as well. MTS's are the only one that doesn't lay eggs AFAIK. They give birth to fuly formed clones one at a time, and therefore reproduce at a much slower rate than the others.
Your beatta will usually eat pond snails or red rams, but MTS's are virtually fish proof. The larger snails like colombian ramshorns, mystery snails and apple snails will need to pair up to reproduce, and some of these lay their eggs above the water line. which would make me think that they could might climb out. their eating habits are similar, but their size needs to be considered in the total bio-load. Apple snails will eat plants, the mystery snails are said to be plant friendly, and the bigger ramshorns I know little about.
The primary concern is a good level of calcium for their shells. If you have soft water, give them some cuttlebone to gnaw on, or add crushed coral to your filter. I do both. You can also feed them crab food which usually is very high in calcium.
dave