It is my first hardy, actually my first tool. I have started with a 1" round bar 40" long of 1045. I have tapered it down to 3/4" to fit my anvil and it slides in to about 1.5 ". 

The rod is too tall to upset on my anvil so I need to cut a piece off.

 

Q1. how much do I need above the shank?

 

3-4 inches or more?

depends a lot on how you want the hardy to look.

Ok so I cut it off at 5" and tried to upset it to create some shoulders which didnt really work for me. I flattened and flared out the service end which turned out alright. It wound up being a flat side hot cut rather than a peaked. I still need to clean it up.