100 = overkill IMO. I have 20 fish in my 180, run an aquaeuro 400 skimmer, feed several times a day with a high quality food, and vodka + vinegar dose. My clean up crew consists of 1 blue leg hermit, roughly 15 astraea snails, 3 nerites, 1 turbo, 1 nassarius, one orange linkia star and 1 urchin......For fish that serve a purpose I have a yellow tang, and a goldenhead sleeper goby. Also, my wrasses help stir the sand, and are also the reason I don't have more nassarius, I really don't want a $1 snail spooking my potters leopard wrasse pair lol. Go with 100 and sure they will live for a while, but if you keep your parameters good your just going to lose a bunch and kill your #s and water quality anyways. Start small and work your way up is the way to go IMO.
Also, I think it is important to have a mixture of the different types, understandable if you don't want a turbo or urchin but I would atleast do astraea's, nerites, with cerith's and nasarius optional since they both go in the sand and could spook snad dwelling fish (which with my pair I don't find it worth the risk), along with some hermits.
FWIW, I clean my front glass once a week- every other week, and have never cleaned the back or sides (inwall tank). Those 3 sides get some algae build up, but its not bad and doesn't last long before the crew gets to it. The tang loves it too since I've never fed nori and it is still happy, healthy and thick :)
