Thanks for the soldered lug tutorial and other updates
BTW, although controller failures are uncommon, they do happen. I've seen an example of an early model Altrax controller that failed while coupled to an Etek. The MOSFETs shorted which = full power from the batteries to the motor. Also someone on another EV forum I'm a member of was injured when their controller failed WOT and they crashed.
A neat place for your second/disconnect contactor would be wired into the brake circuit. What happens when things go bad? You go for the brakes! My EVT 168 electric scooter has a brake cutout where if the brakes are activated while the throttle is open the controller cuts out and doesn't restore power for two seconds after the brake is released.