Agreed, the solaris is superb.
There are also many huge specimens shown online from Australia, from 1996 R.Schulz seed.
I don't consider C.solaris that rare though, I have around 250 myself all grown from habitat seed.
(although not as large as the show plant)
But, I do like to create many 'multiple offsetting' plants in any Copiapoa species much earlier,
I do it by chopping heads off 3cm Copiapoa seedlings, creating much faster growing clumps in much less growing time.
C.solaris at 10cm.