Too many times someone invents a "specialty tool" where not only is it ridiculously over priced but it's touted increased efficiency is oftentimes dubious. I've been using the same basic Craftsman allen wrench (non-ball end) for decades now with never a problem. The crux of the matter is, the tool's metal has to be very hard and it's size has to be most precise.

As always, this is merely IMO where YMMV.

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You dig?

Mostly all good advise. I especially like the tools bluesky636 mentioned. What's important is not to get carried away adjusting, do it an eight turn at a time. If a ball end does any damage, it's your heavy handedness, not the fault of the tool. This will also give you an idea of what's going on before you do any damage. And, make sure your turning in the direction that will give you the desired fix. In other words make sure you know what your doing.