A well crimped 'crimp' onto bare wires is the best connection.
Some of the ratchet crimp tools are not that great unless very specific to the type of connector (usually very expensive) and even then they don't always close the end part (bit that grips the insulation) properly. I see this with professional cables supplied for my work that sometimes require 'attention'.
Best crimpers I've found (without spending silly money) for superseal are these;
https://www.amazon.co.uk/Universal-C.../dp/B002L6HJ8W they do require 2 operations; one for the cable and a second for the insulation as they are too narrow to crimp both together but they make a strong, neat crimp. They also make them in different size ranges but the PA-21 is spot-on for the AMP superseal as used on bikes and many other small connectors.