Casters for Wilson Sophia 2

I was interested in repositioning my Wilson Sophia 2 loudspeakers, but the Sophia 2s didn't come with casters. I'm told that all Wilson casters, including those for the Sasha and Sophia 3 would be an identical fit. Does anyone have a set that aren't in use and could be bought or borrowed? I found the price of a new set to be quite steep.

Room dimensions are 11' x 16' x 9'. Any opinions or experience on final placement would also be appreciated.
Plastic sliders worked perfectly, and at a cost of only 8 dollars. For anyone with the same idea, I'd recommend using somewhat larger spike floor protectors as they are prone to tilt on the soft side of the slider if too small. I used the floor spike protectors from an old equipment rack instead of the Wilson supplied larger ones, and nearly impaled my hand. If you let the weight of the cabinet settle them in for a minute or two before trying to relocate the speakers, you'll be fine.

Wish I could add photos to better explain this.
Place each Wilson brass spike floor protector in the appropriately sized magic slider, edge sliders under each spike and move the speakers around the hardwood floor to your heart's content.
Great idea! I'll bet they have discs, or something like it, for hardwood floors too. Thanks for your response!
Get those plastic discs that you put under furniture to slide it around. When you find a spot for your speakers, remove the discs.