Yeah I seem to be having the same problem, where my hands go crazy in scale. But my problem has absolutly nothing to do with scaling, Im getting it from just animating with fbik (Yes im using ctrl F) and changing between pinning modes.

Im gonna check more forums to see if this happened to anyone else now.

Anyways if you still need help scaling your character, i think i found out that they did something pretty neat in maya 8.5. You used to have to select every bone in the skeleton, but now you only have to select the root joint (or atleast I only had to do that).

As for the rigging, i think i had no problems doing it, but if I did, I would have just deleted the fbik, scaled it then added the fbik again. (Since its only 1 click)