No one can tell you how many you will have because we don’t know how much food is in your tank/ substrate/ decaying plants/ algae etc.
If you don’t mind them too much just keep feeding to a minimum and physically remove them by baiting with lettuce occasionally or crushing them against the wall for fish to eat.
If you want them gone you could add a smaller assassin snail. I wouldn’t add a group if you have larger snails you don’t want to become prey. (Or move the snails you want to keep to another tank for a while. ) Assassins will focus on snails in their preferred size but there have been reports of groups ganging up on larger snails. I keep mine in a tank separated from any dwarf shrimp or smaller nerites. There is one large nerite in the tank that I only see rarely but I think he’s still there. (My tank is super dense with plants so sometimes I go a while without seeing it but I’ve never found a shell) so I think my assassin is just scavenging the gravel these days.
Lol I kinda feel bad for the guy and was going to take him back to my lfs
since I have no more little snails in there but with everyone practically on lock down that seems an unwise reason for a trip out! Once I get new shrimp I may move him to my dwarf shrimp tank that is currently battling a bacterial infection. Having a predator in there taking out the weak/ sick shrimp may actually improve the health of the colony in this case...