When I downloaded this mod, I checked the X tensioner and you will need the original Prusa pulley 623, but If you wanna use Caribou pulley 2gt 16T Toothless, you can check this pulley is “dancing” inside tensioner.
I prefer little pulley because with this pulley the X belt is aligned.
The Prusa pulley (623) width is 9mm and inside tensioner dimension is 9,5mm.
The Caribou pulley (2gt16T) width is 8.5mm and inside dimension tensioner I modified to 9mm.
Now you can use this little and nice pulley with this excellent X tensioner.
The 2 printer photos are linear rail mods, not compatible with this tensioner, I am only showing these photos to make the X-belt alignment visible.
The author remixed this model.