One thing you can do to simplify the problem is cut back on the feedings. Snails generally proliferate so massively because there is ample food available to keep them going. If you feed only enough for the fish, you should see less and less..... you can also try the lettuce (or any other green veg) in the shot glass trick.... I'm not so sure how well it works because I've never tried it but might be worth a try if you're limited on the available fish is your area.
Good Luck