I like to do about 40% ceriths, 30% hermits, and the remaining 30% a mix of specialized stuff. A few astrea, a few nassarius or conch type snails, maybe a turbo, maybe an emerald crab, a shrimp. Ceriths seem to be the overall MVP in my opinion.
I like the snails over the crabs personally.
Fighting conch will be your best sandbed cleaner. Also like nix I love the cerith snails, they can go on the glass , sand and rock. Another great snail is the trochus
Longest living snail I have is a bumblebee snail. I love that thing gets everywhere.
+1 on conch for the sand bed. For crabs I have best luck with the blue legged hermits. Had some of those for 2+years while the scarlet legged crabs have only lasted months.
If you don’t glue down your corals I would suggest stay away from turbo snails unless you have a green hair algae issue.
I just got done watching this video, Week 23: Reef tank clean-up crews: 40 or 400? | 52 Weeks of Reefing #BRS160 and found it to be a reasonable no nonsense explanation of Clean up crews and how we all get oversold on what and how many to buy with a couple pointers on what to buy too. I am going through parts of the series now and just finished this one and learned a lot