1970 Dart Horn Issue

So the previous owner decided to put an after market steering wheel on the car. In his great wisdom he decided not to wire the horn to the steering wheel, but instead to a button on the dash.

I am planning on buying an original steering wheel and wiring the horn back to where it is supposed to be. I have a few questions regarding this.

1. What wire should I buy for this? I asked a few people, and they told me wire was wire and it shouldn't matter. Maybe, but I don't believe this. What would you suggest?

2. Is there an easy way to get the wire back through the steering column? I was going to take the steering wheel off, and try to thread the wire back down, which may or may not work. I have a feeling the suggestion will be to drop the steering column and do it that way, which I have no idea how to do.

3. What would be the best way to patch the hole that was drilled into the dash to install this silly horn button? While this will never be a show car, I would like it to look as nice as possible.

Any ideas??

Thanks!