Siberian Husky Or Australian Shepherd?

I fianly get a dog of my own. My brother has a mini aussie which he never took much interest in. I have trained her and raised her since she was little. I have certified her as a therapy dog and I compet in agility competitions with her. I need a bigger dog as I am going to get into skijoring/scooterjoring. I have always dreamed of an Siberian husky since I was little. I eventually want to have a sled dog team. As around my area they hold sled dog races. I am plaanning on getting a dog now and training it to be a skijoring dog that way it will have a start for mushing. After I have a little experiance from training it I will get another dog in a year or two and then a few more. Within 4 years I plan on having a sled dog team of 5. There is a 5 dog team catagory at the sled dog race I will be in. I have always loved huskies but recently I have been reaserching and huskies are not good farm dogs. and they can’t be trusted off leash without YEARS of training. I think it would be great to have a dog that could help with the sheep aswell. So I am thinking of getting a full sized australian shepherd. Could a full sized aussie do skijoring? What breed? Thanks