I think hydro is easier, the hardest thing is getting it all setup after that you just need to keep an eye on the water quality which you should do with pots as well. also helps cut down on the mess, But ofcorse to each there own:)
one more thing then i'll shut the hell up :) I would be concernd of over heating while your gone. i'm sure you'll figure something out. Blaze on brotha
If you take the door of the hing you can put it back when your done and no one would be the wiser. or you can make a room inside of your closet with fans and the whole deal. and open the door when your home to let fresh air in. If that doesn't work i don't really see any other option for ya
Not sure on the 400 in a 430. personaly i wouldn't do it...............
The closets a hard one hmm....well, if you don't have a problem with people finding your plant try taking the door off the hing and make A wall/door with some plastic that way you can cut all the holes you need.