If you have no option other than Coromandel to Chennai, then take Bangalore Mail at 11:15 PM. You will have enough buffer time. I wont advise you to take Kaveri because it arrives at SBC too early though you can board Kaveri at MAS without any problem even if Coromandel is delayed. If you dont have any issues with the early arrival of Kaveri, then you can take reserve your ticket in Kaveri also.