I very strongly advise against getting a H. magnifica solely for your clown's benefit. They are very, very difficult to keep. It would be much easier to find a suitable clown for the hardy BTA. There are several clowns that naturally host in them.
I've seen or heard of percs hosting in goniopora, euphyllia (hammer, torch, frogspawn, bubble), even in xenia. They seem to like the tactile stimulation of tentacles against their bodies.