Hey Mike,
I'm not too sure what kind of nuts are on those amp's posts. If they are the standard size hex nut, the plastic tool that comes with a toilet seat works wonderfully. I use one on my VMPS RM40 speaker's binding posts. It gives your a good grip, and doesn't bugger up the metal on the posts. You can torque it very tight if needed. If that doesn't fit because of the shape of the nut on the post, I tried to help--and have a nice day.
Bob