The seat height for this chair is 22 inches. You could use a footstool with this chair if you needed.

The assistance you need is stronger hands. I used to build sets so I am no stranger to construction and tools but I had to get one of the guys here in the office to snap my wheels into the base. You can also cover the wheels and gently tap on them with a mallet if you can not get them in by hand.

We warranty the whole chair for the first year. However we do not cover the ball against non defective issues such as your cat, or your child puncturing the ball with something pointy. In the case that your ball is some how damaged by accident you can purchase a replacement ball for the chair.

You wont get as much of core exercise with the chair because you are taking the balancing aspect out of the ball equation. However because the ball forces you to sit straight up you are having to use your core to support yourself. The major benefit of this chair is the proper back support more than the core workout.

If you email ProductSpecialist@gaiam.com we can get something sent over to you.