You are correct. You cannot balance a spinner on the Top Flite balancer

You need a Dubro or a High Point Balancer. You lower the front wheel stand and raise the rear one. The Arbor goes on top of the front wheels and under the rear wheels. The spinner assembly is put on the end of the arbor spindle rod out in front of the balancer

PS.... I must add that you have to put one of the wheel stands up into the middle of the balancer body.