I'll see what I can do without getting into any trouble.

The large servo arms that come with the newer Hitec digitals are supposed to be made from the same stuff that the karbonite gear trains are made of. It's allegedly stronger and stiffer that what had been previously available from other manufacturers. Dubro is one of the "other manufacturers".

In any case, it's not the best idea to surface mount a ball link to any of the plastic servo arms. They will all twist under the right loads, and many will eventually break under those conditions. Aluminum arms are a better choice if the use of ball link hardware is selected.