I had a problem getting the top bearing blocks on my X carriage (https://www.thingiverse.com/thing:2193695) properly aligned on my AM8 build when they were fitted with IGUS DryLin RJ4JP-01-08 bearings. I found out, that it was caused by some sort of misalignment of the original SC8UU aluminum blocks, which caused the bearings to bind.
In order to avoid this issue, I remixed the original bearing block to hold 2 LM8UU size IGUS bearings, and mounted it onto my baseplate just using the 4 outer holes. Now the carriage moves without binding.
I had to set the internal diameter til 15.3mm in order to get the IGUS bearing to fit properly, so it wasn't loose, and it wasn't required to use a lot of force to insert the bearings. Use fusion360 to adjust the diameter, if it is too loose or tight when printed on your own printer - or send me a message, if you need a custom sized STL.
Using 3 outline/perimeter shells - and 8 top/bottom layers