I would just tin the wire, keeping strands together, preventing them from fraying and gives a nice solid connection to the terminal.
It also provides a failure point - the wire will break at the end of the solder joint.
If you aren't handling much current (e.g. this is data, or low power) the ferrules are OK. The screw terminals will clamp down on a bundle of stranded wire and make a good solid connection, in sort of the same way that a crimp connector clamps down on stranded wire.
-j