I've kept lamprologus ocellatus "gold" in a 20g and in a 40g, they were much happier in the larger tank where I had 2m 2f, both females were breeding with the alpha male while they all kept the spare male behind the filter. In a 20g you should be able to house 1m 2f.
You make it sound like people on cichlid-forum DON'T have experience of keeping them, btw, that's not true. If you search the Tanganyikan forum for "ocellatus" I'd bet you'd get more than a hundred hits full of experienced input.
Anyway, that's not what we're here for!
Feeding them is not a problem at all, live food is not a necessity,m though BBS would be taken readily especially by fry. They have voracious appetites and mine used to enjoy Tetra Prima, Hikari Cichlid Gold baby pellets, frozen cichlid diet and mysis shrimp.
My tips for keeping them? Firstly buy good quality stock and don't get fobbed off with 3 males like I first did! You can tell the females from the white flash at the rear of the dorsal and anal fins, they are also smaller than the males which reach just over 2". When settin gout the tank, add about 2" sand for the substrate and space the shells around, at least 2 shells per fish to start out. Add a few rocks to the rear or side of the tank for fry to explore and females to escape an over amorous male! You don't need plants and you don't need dither or target fish either - tetras, white clouds etc will be zapped by the territorial occies. I don't think the 20 is big enough for a bristlenose pleco or syno petricola, so keep the tank a species tank for best results.
The female occies will dig around their chosen shell then bury it until just the opening is visible. They like to move their shells and move between shells every now and then. This is part of the fun with occies they are constantly moving sand, burying and uncovering shells and this is why you don't want gravel in the tank. They struggle with gravel and you don't get to see them bulldozing.
Hope you get them and I'm sure you won't regret it.
