Kapton tape should arrive in a week so that I can attach it to the heatbed.
As far as the problems I was having earlier. I addressed them mostly by cutting off a bit of the sleeve on the thermistor, this made getting the wires around each other easier. I was able then to slide the ferrels over the wires… and to crimp it, I used the wire stripper… gently. I just sorta crimped it up and down so that it was all firmly attached and connected together, which I imagine is the important part. Then I pulled the heat shrink material over it and put the flame to it.