PDL I ordered a couple of your guides and decided to retrofit on into one of my Slot.it GT1's which is a new release.
I noted that even on this car the guide wobbled 360 degrees.
I followed the instructions on your website and about 20 minutes later I now have the smoothest play free guide I have ever seen a plastic car.
I did use a thinner 3 mm washer and I am looking to replace the provided 6-32 nut with a more compact unit to fit under some cars.
I wish I had bought some of these sooner.