Ahhh......the Toycrafter 4 inch top. That's a pretty tough top and not too heavy that would hurt a stage. I need to revisit that. Good ole Don Olney tried pretty hard with that. He said it was a problem, though. Only a few came out balanced as the plastic would not spread out evenly when they were made so he finally abandoned the project. I was once at a juggling festival in Cincinnati and Mark was there (maybe almost 20 years ago) and he let me use his 4 inch Don Olney. I practiced with it for a long long time and when I finally boomeranged it (with the nine foot rope) the thrill was so great that I'm convinced that was one of the reasons I started moving more into top spinning.
Yes, I wonder how many of those are still around?