[@greywolf375]
Bigger the thing being sealed, the more Aeon used. I would say sealing an object of about a 20 foot size(height, width, and length) would be the limit before using too much. Remember, you have only just recently finished your 1st year. 

Sealing an actual sentient being is a different story, having to use blood to fuel the sealing along with Aeon. The stronger the sentient's control over them self and Aeon, the hard they'll be to seal. The blood amount is up to your discretion.