Freewheel diodes:
200v 60amp, PART # STTH6002CW
That's a good tip about isolating the drain from the heat spreader inside the controller. I was also looking into connecting the drain directly to the heat spreader, and then isolating the heat spreader from the heat sink that will be outside the controller. I think the latter would be best.
That's an awesome point Ben. I've been thinking about the connector locations a bit. Pin #1 on the Curtis, as you were saying is full pack B+. On this controller it will be +12v from the auxiliary battery. There's no reason at all it would have to be anywhere near the big B+, B-, and M- leads. The M- lead could be on the other end of the controller too. It might make it easier to have a connection to the motor on one side, and the B+ and B- on the other end. It would give plenty of space for the lugs. Also, I think I could get away with 3 pieces of copper bus bar that wouldn't have to be cut at all! How's that for open source! haha. Only holes need to be drilled in them. Everyone has a drill! Well, everyone that wants to build a controller, probably.
I found a Hall Effect Current Sensor that has a big enough of a hole so that 0.75" wide bus bar can be used. I think 0.75" is just about right for attaching lugs. The other current sensor had an opening that allowed for only about 0.5" bus bar, so that the bus bar would have to be cut from a wider piece, so the ends would be big enough to attach lugs, but most of the length would be about 0.5". I'm trying to avoid having a band saw be a part of the required tools for assembly!