Hello Shelbie and welcome to our family.
So glad you could give Erwin a new forever home, do you know his approximate age? That would help some in integrating him into your home but since he has been a breeder bird it might take a long time to gain his trust and he may never fully develop into a pet grey but you can enrich his life even if you are never able to handle him.
I wouldn't try getting him to step up for you, just stay with giving him treats from your hand right now since he has a fear of hands, you will just have to spend some time each day sitting by his cage and talking softly to him, maybe reading him a book or newspaper as it doesn't matter what you say as long as you are talking to him. Let him be the one to want to interact with you and it will take lots of time and much patience on your part but will be well worth it. Don't push him for more than he is willing to give at this time as you don't want to do anything to give him reason to distrust you.
If he was kept in a cage all day then that is what he knows and sitting on a perch all day was probably what he is used to but do provide some toys especially things he can chew on and if that perch is one of those round wooden kind it should be replaced with some that are of differing widths so as to exercise their feet.
Irwin is a handsome Tag and yes it is normal for him to move to the other side of the cage if you get too close, it takes time to build trust especially with a mature bird so take it slow and easy, you have made some progress so think in terms of short steps and I bet in the coming weeks and months he progresses more steps, keep us informed.