Graham Supreme 12" tonearm counterwieght problem

Purchased 12 inch graham supreme tonearm.  Counterweight appears too light for use with multipel cartriges.  Has anyone had this problem?  Awaiting response from Graham Engineering but none yet
Hello, Did your arm come with an additional smaller counter weight that slides onto the end of the shaft. Mine did. Without it, it would not be possible to use high mass cartridges. I am using this same tonearm with a Benz LPS cartridge. This cartridge is heavy at 16 grams and with the additional end weight I have no problem with setup. Hope this information helps.
Good luck with service on Graham!!