If you have a push button starter you will probably have another switch to put power to the coil. whatever side of the battery is ground, (in your case the pos post) that is the post of the coil that goes to the points. The other side should have power when the key is on. The big coil wire in the center goes to the cap. If you are using a 12v test light on a 6v system, the light will be real dim. I don't like flashing the wire at the battery. Creating a spark near the battery is a good way to blow it up in your face. Not a good time!!
That's true but unless the battery is being charged there is no risk of it exploding. Next time hook the wire to the battery and touch it to the post.