I've got the same question and I'm having trouble finding answers. I found a nice Clivia growing in a shade house locally about a mile inland from the coast. In Dana Point I see some growing in strong light on east walls of houses in shade that I'd suggest was "partial"... that is no direct sun. But I've also seen some which bloomed profusely at the NE corder of a gate/wall with what seems pretty strong exposure to sun until at least noon. In this array, it seems that those in the sun bloom a week or two earlier than those in the fuller shade (though strong light).