Christian's actually left it fairly easy for us to challenge this.
He went with Careless conduct, high contact and medium impact.
He could have easily gone with Intentional, high contact and low impact.
I believe both end up with 1 match suspensions but based on previous incidents (someone above posted Selwood - low impact), I would think we have a fair chance of turning around the medium impact down to low (and then a fine), rather than intentional down to careless (as he clearly engaged the contact - whilst not attempting to hit his head).
I reckon knowing this, its a no brainer to appeal, as I reckon we are a good chance to reduce that to low impact bearing in mind the Hawthorn player played the game out. I doubt the Hawks doctors would try and screw us over this.