Andy,
A few thoughts, I tend to agree with Jill, we have showed quite a few Angus over the years and many seem to be goofy when you get around their heads. In fact we are bringing a yearling heifer to the fair this week that is this way. She is puppy dog tame, leads great, the kids get along great with her but if you get around her head she shake it and snorts, doesn't take after anyone or move around but does not want her head messed with.
Also you say she is broke to tie, in my opinion being broke to tie is much different than being tame. Like you we start by letting the calves drag a halter. We then tie them up for a few hours. While they are tied up we start by scratching the side of their tail, the calves really seem to calm down when you do this, we use a scotch comb and work the sides of the tail and 90% of the time the ears go back and the calves just relax. We comb and brush on the calves, the first few times we just concentrate on the back end and over the next few times slowly move up. We never mess with the heads or neck the first 4 or 5 times, in fact we use a show stick to pull off the halter for the first couple of weeks. My experience is that calves get scared when you reach for or touch their head so anything you can do to avoid this is best until they are tame. I have always tried to teach my kids that we don't really break our calves to lead we get them tame and then they lead. We don't manhandle them a lot we just spend a lot of time when they are tied up brushing, rinsing, combing, touching, walking between them, anything we can do to get them used to being touched. I am not going to tell you this works everytime, in fact we gave up on one of our heifers last year becuase she wouldn't calm down and it wasn't worth getting someone hurt, but it has worked well for us over the years. We still have some struggles and still have some runners once in a while but while tame calves may still give the kids a fight or get away once in a while I don't worry as much about the kids getting hurt.
Mike