So what I'm reading is it takes a lot of balls to move a heavy safe....Guy who moved safes told me this is what he did. He'd go buy old range balls. Once the balls are under it, it moves with ease. Just need a helper to keep sweeping balls under it. Tough going over carpet, but it still works. Over a hard floor, it glides.
Guy who installed mine had a special dolly/hand truck that would roll and change direction easily. I helped spot him going through one real tight spot, but he moved it and installed it himself.