Wilson Audio speaker jacks

Opinions on Wilson Audio speaker jacks. Anyone use them?
I am referring to the jacks to move heavy speakers around.
I found the Wilson jack extremely useful for precise placement and toe-in of my Maxx2 speakers. You can roll the speakers on their casters to optimal positions but when you go to replace the casters with spikes without using the jack, you will need at least two people and the position and toe-in can change because you don't have complete control how the speaker is lowered. Since you'll be able to replace only two casters at a time, some wobbling and rotation will occur. Once the speakers are on their spikes it is very difficult to make position and toe-in corrections. (They are 410 lbs each.) However, with the jack, the replacement is a one person job: Determine the optimal position and toe-in with the casters on, slide the jack under, lift the speaker straight up, replace all 4 casters, lower the speaker straight down without any wobbling, and then slide the jack out.
I have never seen them.Post pics if possible.Guessing they are common and not custom as jacks are USUALLY designed for many loads/jobs.Is it the price or usefulness you are concerned about?
Wilson Audio makes the jack for the Maxx speaker which I have used (borrowed from the previous owner, he will not sell me the jack) with great success. It is a work of art, machined from billet aluminum and very slim to fit under the speakers. I think that you can buy one from Wilson for nearly $1000, which is consistent with his overall pricing policies! I'm sending pictures to a friend who has a home metal shop to see if he can reproduce a similar jack for me.