Hi TasV.
I'd say haseltoniana, or longistaminea, or tenebrosa... just going by pics I have found. When all is said and done, give the lumpers time and they'll all be C. haseltoniana or something anyway...
Check out these links:
Copiapoa cinerea & tenebrosa
Copiapoa longistaminea
Copiapoa gigantea
Copiapoa haseltoniana
Cheers for now
CP