One of my friends also have a Kymco Super 8 125cc and he has put 14 rolls on her to not have to run so fast idle.
Idling speed is adjusted by the idling screw (carburetor) or software (injected), has nothing to do with the roller weights.
Perhaps you should buy in Germany. "MSA" is the German Kymco importer for now more than 16 years and has a good reputation.
The brake pads of a disc brake should have a wear indicator. No screwing needed for an inspection, but perhaps a torch. Look into your manual.
And if you can read German, you might want to visit the German Kymco forum
http://www.zzip.de/forum/index.php , you won't be the first Danish there.