Ring terminals are the most secure type of tongue style connectors because they cannot slip off a screw or stud. They should be used on all critical circuits. ABYC calls for the ring size of the terminal to match the size of the screw it is connecting to. These #6 rings match the size of the screw in the 2400 series of terminal blocks by Blue Sea.
Ancor's Marine Grade terminals differ from automotive terminals by being designed for the harsh marine environment. Nylon insulators are easy to crimp and will not split. Barrels are designed to tightly grip the wire with the least effort. Tinned copper gives the least electrical resistance but the most corrosion protection.