As Black, I play three of the variations of open Sicilian. As it turns out, I managed to choose systems where White is unlikely to castle to c1. I got started playing the Sicilian by inventing my own: 1 e4 c5 2 Nf3 e6 3 d4 cxd4 4 Nxd4 d5. When I tried to play that, my opponents almost all went 2 Bc4 and many added Nc3. I couldn’t play …d5 but I found …a6…b5 effective. Soon I took up studying the Kan because it felt similar to what had been occurring in my games. I played exclusively the Kan for a number of years.
I play the English as White, and in learning the Symmetrical English I needed material on the Maroczy Bind Accelerated Dragon. The Accelerated Dragon materials covered Bc4 lines also. After studying those Accelerated Dragon materials, I played it in its Sicilian form (with the ...Qa5 idea to discourage castling to c1).
Next I added the Sveshnikov to my repertoire. I was always impressed with the activity Black can achieve in the Sveshnikov. I actually regarded the Sveshnikov as "sexy" because the theory was daunting, it was the newest open Sicilian, and the exemplary games were spectacular.
I would love to be able to play a fourth variation.