Is the cockpit coming roughly level with the top of the tiller at the current mounting point (about 16" in front of the pivot)? If so I'd extend the ram instead of using one of those cantilever mounts.
There are photos here:
Raymarine ST2000+ Installation - AlexAndChristine's Photos | SmugMug
When it's removed the only sights of it existing are a small pin in the tiller and a small piece of brass on the edge of the cockpit. The black section of the ram is the extension. I think it was about $30.
I don't like the cantilever mount because it takes away functional bench area in the cockpit.