We use a couple different versions of fold-up stands (images easily found if you Google "race kart stand") that are essentially a base with tires and two T shaped arms. We're tall too but have found these stands put the kart at a good working level. If you can weld you can always cut and lengthen those Ts. The fold-up stands that form a roll-around X also work, but might be more difficult to modify if you need more height.
