@bberger for my last three duet machines I did not have to crimp anything with a special or universal tool. Working with the hotend to customize for me has not needed customized wireing harness as all my changes are from the Smart Effector base.
I feel that universal crimps give poor results more often than good and a specifically designed tool should be used when the hardware was designed for one.
If we went to ferrule for the heater wiring I would personally have no problem as I do have a toll specifically for that. However, I would caution against it due to my desire to keep from forcing people to buy tools.
Perhaps one of the Duet people can correct me on the requirement to have a molex tool to build a Duet system?
I know several vendors of Duet boards in the US use alternative connects to the Molex ones due to supply but they are compatible with the male ends on the board.