The replacement Yamaha rollers work great, their different than the stock 2017 rollers. My original rollers flat spotted at just over 400 km. My replacement Yamaha rollers changed on warranty now have 2200 km on and look perfect.
For your 8DN belt
Add the small washers ( one more to start with) on your bolt ( the bolt that holds your secondary clutch on) to the clutch side of the big washer to make your belt tighter ,
I’m sure more guys will chime in with replies.