Dear Carl: You can go to: www.audiolimits.com or to
www.walrus.co.uk, these two are Audiocraft dealers and maybe you can buy there a counterweight that match your cartridge or a new arm wand that match your cartridge/counterweight.
I own the AC 4400 with three diferents arm wand, one of these are the s shaped that needs a lateral counterweight LWS-1. When the cartridge is a heavy one then you have to use the subweight: SW-12 that you screw at the back of the tonearm ( where the main counterweight goes ). Now, the main counterweight is in reality a double weight, I try to explain this: the counterweight has two rings one is the gauge ring ( it is at front ) the second ring ( behind the gauge ring ) is an adjustement ring, if you slide this ring the counterweight split in two parts and in this way you can have a bigger ( large ) counterweight with more weight at the back of the tonearm.
The english is not my native language, so I'm sorry for it.
Regards and enjoy the music.
Raul.