So basically the discs are pretty much worthless.
I still wish there would begin designing more racks that have casters. I use a customized rack made from steel that comes with casters, from anchor. It's well-made extremely solid and was really quite reasonable pricewise. i think it’s insane to put a 150 pound amplifier on a rack that does not move and requires two people to help out.
How cool it would be to design a lift for internal use that you could wheel around to move amplifiers and speakers. Like the lift they use on the back of a pick up truck when they quickly move Indy cars from the road when they crash but of course on a different scale and separated from a pick up truck.