X2 have called them many times with questions always helpful.
Also I saw a show once about new inventions probably a couple years back.
A couple guys had invented a hydraulic creeper and were trying to get someone to back them. the thing was really slick. You sat in it like a chair and could maneuver around the car then when you wanted to go under the car you pushed a button and the hydraulics would lower and level the chair into a creeper. It worked very well and they had several mechanics with bad backs try it. I think an excellent tool for a handy caped person. I don't know if they made a go of it or not. Have not seen them advertised.