Jelco Tk-850l tonearm counterbalance

I'm using a Soundsmith Zephyr MIMC ES star cartridge, when setting vtf the counterbalance is all the way at the end.  When I dial it in there is no way to secure it, sometimes as I'm putting on the dust cover it moves and I have to do it all again.  Something that would help is a heavier counterbalance.  If you have this tonearm and problem how have you dealt with this.  On the other hand I'm getting a lot of experience doing this, a little frustrated.

I think there's a heavier counterweight available from Jelco or an aftermarket source.  Another option might be to use a lighter headshell.  Shaving a gram or two at the cartridge end will make a difference at the counterweight end.    

How about gluing a steel or brass washer to the counterweight making sure its hole fits over the stub? Have you tried sliding the main ring weight?

Thanks, I suppose using double sided tape to see if it works.