IMO, avoid the hermits altogether - they are omniverous adn can cause problems with certain snails. Which brings me to the second part- get a variety of snails - different snails each seem to have different algae "preferences", so a variety works better than just one or two species.
I'd only buy a couple of turbos and a couple of astreas (both regularly available from LFSs). I'd buy a dozen each of cerith and nerites (usually available only MO), a couple of fighting conches (if you have a sandbed - these can be found either MO or at some LFSs), about 1/2 dozen nassarius snails, and a few trochus (again, sometimes available at LFSs).
FWIW,
Kevin