One nice feature of mass finishing is the labor is a lot less than hand finishing. I'm no expert at vibratory finishing but here is what I've noticed. I have triangle shaped ceramics that leave the aluminum fairly bright. I have abrasive impregnated plastic rods cut at an angle that do a really good job of burr removal and leave a fairly dull surface.
I would contact a supplier of media and tell them the finish you're looking for. The will steer you in the right direction.

Derek