Wires on the coil reversed will do little either way. No real harm. But, coil is designed to work with the proper current direction so I would think there might be a small advantage with ignition to + and - to the points. Has to do with the field collapse and the induction to the secondary coil. The fancy word is hysteresis loss. Just a way to measure how efficient the coil/transformer is working. Might make the coil run a little warmer, and it might not. Reversing switch? Might keep the fan motor running the right way? Just kidding I have no experience with a set up like that.
