The crimp tool for Metripack is $30.
When I think of strain relief, I think of this:
It's there to prevent the cable jacket from experiencing too tight of a bend radius. And its stiffness needs to be in balance with the stiffness of the cable. Too soft and it does nothing. Too hard and it simply moves the 'kink' point further down the cable.
One of the nice things about Deutschs is they have external bracket attachments that can be used to secure the connector body.