Hello @juicyjesus! Welcome!
Nut spin doesn’t sound good, mine were tight fit, so tight I had to use pliers to push the nut in for some parts. What filament, printer and settings are you using? Used Overture PLA on Ender 3 Max, 0.6mm nozzle, 0.32 layer height. I used infill % recommended in LR3 Docs plus additional 10%
https://teachingtechyt.github.io/calibration.html helped me calibrate dimension accuracy, flow, temperature, speeds and the million other settings required to find a sweet spot to print parts.
Printed bunch of calibration cubes and test temperature tower and test retraction towers before printing LR3 parts.
Only tensioned belts with ~7lbs of pressure, hard to gauge, but it’s less tension than what I first thought would be required. Forum search for recommended belt tension may help too.