I did not pop it out, and I am not sure if I am. I think I am going to keep it in the ball. With the loop at the top you can clip in handels for farmers walks
As far as the grout, it holds up great (although it will crackif not supported properly on a countertop), and the specs seem to show much higher psi than concrete. I have done two outside countertops, and a interior countertop with the grout over the past 6 years, holds up well. If I was going to make a complete round stone out of it, I would use fibers. There are a few vendors that make countertop blend that does not show the "fuzz" from the fibers in the finished product, and needs no rebar. That stuff would be the deal for a heavy use stone. http://www.scpusa.com/index.php?q=node/60
Those guys are doing overhangs without rebar.