Change size of armature bones? I want to be able to do is change the size of the big bone a bit so I can actually see what I'm animating.

I want to be able to wireframe the armature so I can see the hands.

So in other words, I want to be able to see the fingers, making the whole armature a lot thinner but not bigger or longer, and the then be able to see through it.
To adjust the size of the B-Bone display type in Blender, enter Edit mode and use CtrlAltS. It will scale while keeping it constrained. To scale on a specific axis, select the desired axis after triggering this with X, Y or X.