So, my Stemshavers arrived on Friday and I have had enough time to test them out. Below is an album of to show my testing. Be sure to embiggen the pictures for a better view.
https://imgur.com/a/iEZoM9eTop row is unshaved, bottom row has been shaved. I'm sure the pictures highlight my findings.
After shaving each stem, I found it much easier to remove keycaps. When comparing to unshaved stems, the shaved stems are significantly improved.
I used some extra crappy, cheap DSA caps, which pretty much crack on anything they come in contact with. That includes Zealios and Cherry MX switches. Though, when used on the unshaved MX Clear, was so tight it wouldn't come off and then also had no signs of stress marks or cracks. At the end of the album is a comparison between the two.
Personally, I recommend getting the wooden handle one as it makes the process so much easier. Especially as you can see that my handle free one got stuck, in some sort of Excalibur situation.
When shaving you do have to shave twice, from the opposite angle. As in, if you shave from the top, you will need to shave from the bottom to hit both sides of the stem.
I used an art knife to shave off the unwanted excess plastic. This helps when you put keycaps back on so they sit properly.
I will be buying a stack with handles as these work and ultimately do exactly what I need.