I made a holder out of a rectangle scrap of 3/4 inch plywood (you can use whatever you've got and if it's thin use two layers). Toward one end, about 4 inches from the end, you cut a hole big enough to allow a socket through to get to the big nut holding the variator. Then you drill 4 holes through in a square pattern about 3 or 4 inches on each side, centered on the big hole you drilled for the socket, and put through large bolts with a washer under the head and a large washer and nut on the other side (facing the variator) with enough bolt sticking out so that they reach between the vanes on the variator. The plywood should be shaped so it covers the variator and reaches far enough in one direction to jam against the frame of the scooter or the floor when you rotate the variator with the hole over the variator nut and the 4 bolts stuck between the vanes of the variator. Then put your socket through the plywood onto the nut and unscrew it.
If the scooter wants to rise up off the floor while you are unscrewing the nut, either sit on it yourself or get your overweight brother-in-law to sit there while you push on the breaker bar.
If this isn't clear, reply and I'll take a photo of the one I made.