Here are the connector parts you could use. They are era correct 6 way Packard 56 series. One female shell and one male shell. Your J. carter contacts will snap into one of these. Then you need the female contact for your harness ends. Del City, Terminal Supply and Way Tech have these but probably have minimum orders. Buy them where you wish or use the newer thin style connector and just use 6 pins, but don't think the J. carter contacts fit. Not sure.
You can also just splice and leave a service loop for future replacement of switch.
Female shell.
Male shell
Female ContactPage showing contact part numbers vs wire size
