While theoretically you could seal power into the moon, i would not advise it. The point of sealing your excess strength away is to have it for when you need it. The theory of distance still matters in matters of using your power, and i would think that if you sealed your powers in the moon, you would only feel a boost in strength when the moon was full. I do not recommend having your powers on that kind of a schedule for the simple fact that you cant use them when you need them.
Secondly, I do not see why you would seal your powers in another person. I would not recommend it, as your energy could have negative effects on the host. I would recommend, if you are going to seal your powers, to seal them in something that you keep nearby. I have recently taken to storing excess energy in my Ipod, with no negative effects on the electronic.