I am assuming that you are going to Provodenciales and not Grand Turk, South Caicos or Salt Cay. I am not aware of any dive ops on Provo using steel 120's but you should certainly ask. There are several dive ops that can be recommended on Provo. My personal favorite is Caicos Adventures. The best diving is in the boat channel between Provo and West Caicos, off the west side of West Caicos, and near a sand spot called French Cay. There is also some average to above average diving in Grace Bay and off some of the cays near the northeast tip of the island. I have been to Cozumel many times and St. Croix once. TCI is known for its massive walls and large pelagics. There are no gurantees on any one dive but its not unusual to see several turtles, several sharks and some passing eagle rays on one dive. The diving can run hot or cold. I have had some of the best dives of my life in TCI but there have been other trips where I haven't seen a lot of big stuff. My favorite day of diving ever was off West Caicos and involved a humpback and her calf on the surface, dolphins in the water with us, so many eagle rays in a formation that I lost count at 25, and three caribbean reef sharks circling us on our safety stop.