Nice pearls have a bit of a chameleon streak: they change looks in different lights and I would imagine it is a matter of opinion which of these 'looks' is nicer.
Obviously everything changes appearance with lighting (a generalization of "all cats are black in the dark", LOL), precious stones just make one think harder of their appearance and notice changes. and they also bring up the subtle changes in the color and type of lighting that normally most do not (need to) notice ... IMO, in this sense pearls change with lighting...
IMO, orient shows best in day light (directional light), overtone comes up when orient subsides in diffuse lighting, and lustre plays out most in dim 'candle light' when both orient and overtone become harder to notice from a socially acceptable distance (i.e. no staring at a pearl under loupe, but on a wearer).
The best way to see these? Get a couple of loose pearls as separate examples of TOP orient, exotic overtone and great lustre. And let them do the talking. With freshwaters and unusual pearls sold loose this is feasible, and not a bank breaking exercise at all. The only problem with such experiments is that they can make you quite a 'pearl snob'
(a chronic condition that may be rather fun, IHMO)
My 2c.