Originally Posted by My Beau
Definitely check him for ulcers. You don't have to have him scoped - just treat him for a few weeks and if there is improvement, you know that's the problem.
I personally would not treat a horse for a condition the horse may or may not have. Not to mention medications for ulcers are not cheap.
I would check through physical issues first as that sort of behavior while tacking always makes me think something physical. In response to your other questions- I agree with Kevinshorses in that you should not allow these behaviors and you need to establish some respect. A horse walking in circles around me drives me nuts. I usually deal with it by aggressively making them move their feet away from me and in the direction that I so choose.
As for where you should tack him- again I agree with Kevinshorses. Don't do it in stall as you'll have nowhere to go. I also think that the stall should not be associated with ground work and schooling. So I would not tack him up in the stall or school him in the stall for safety reasons and also for my owner personal reasons. If he is phobic about cross ties try to find a safe place to straight tie him OR work on the cross tie issue. Tying with a halter is an essential skill to me and, with few exceptions, a horse who is well versed with giving to pressure will not pull, there are always exceptions but generally speaking.
If you feel nervous about working with him you are only going exacerbate the issues. Find someone in your area that would be willing to come out and give you a couple of pointers.