I just ordered one "Outer Ring" from the lab you referred! They seem oriented to excellent customer service, so they agreed to receive one particularly warped LP I have, for testing before-and-after the clamp, just to see if the warp will be flattened for playback. They will do so in addition to taking photographs and some sort of technical testing before-and-after.
On top if this, they let me free to decline the purchase if the clamp does not flatten this particular LP. That's true customer service, and I will purchase, regardless. There are other benefits besides flattening LPs and eliminating warp-wow: flywheel effect, and damping of LP/stylus vibrations. They also assure me of no reports from users, regarding wear on the bearing.