Installing inspection lamp socket

[IIA]

I finally got a new red socket to replace the one missing from my dash. So I've got 2 questions about it:

1. I've read that it's a good idea to add an inline fuse. What size fuse would be best?

2. There are a bunch of disconnected wires in my dash but none of them have the required ring connector on them so it's not obvious which wire belongs to the socket. How do I decide which one to use? Would any hot wire be sufficient?

[siii8873]

should be a larger brown wire, which I think is fed directly from terminal on solenoid.