Encourage him to stay up on the stand with toys that he likes (more along the lines of a foraging toys that take him a while to use). Train him to go back on top of the stand on command using positive reinforcement (they LOVE pine nuts and they are relatively small so they don't fill up as fast on them). Most important is to not react when he comes after you on the floor, in his eyes its a fun game. He has learned that he can make a very large being move quite quickly on the floor. In his case he is more empowered on the floor than he is vulnerable. If you move when he wants you to then that is encouraging the behavior. When hes on the stand being good, its not as exciting, so you will have to make on top of the stand/cage fun.
I would suggest padding your legs underneath jeans and by a pair of really tough boots. He has to learn that you will not move when he chases you, this will more than likely result in a few bites. You have to take the fun out of it. Over time when he figures out that you do nothing but stand there and give NO reaction (act as though its not happening) he will stop. Its going to take time and I would pad the legs really well.
