D_what, what
cant say said is exactly true for people (like me) who clone using powersaves. Hmm, maybe a little PSA about cloning might be in order?
There are primarily 2 methods for cloning pokemon in gen 6. The most common method is by using powersaves, but this does add extra wear and tear on the pins of your cartridge, which shortens the lifespan of your game over time. That's why many cloners will typically ask to keep a copy in exchange.
Further, any person who clones for you using powersaves will be able to keep a copy of the pokemon cloned, so there's a certain amount of honor code among cloners. That's why you should use discretion when choosing who to clone for you. If you have something that you don't want redistributed, and you get an untrustworthy person to clone for you, well. That's one common reason people are reported to the wifi forum blacklist.
The second method is by using the cloning glitch while trading between 2 3DS's. I wouldn't recommend this method, as it takes some time to get even a single clone, and there is a chance that your pokemon could be lost if done incorrectly.
As for timing, I've generally found the time constraint is in the trade, rather than in the cloning process. When trading pokemon in bulk, you should budget about 1 minute per pokemon. So if you're going to get 1 pokemon cloned, that's 1 minute to send the pokemon to the cloner, maybe 5 minutes to clone, plus 5 minutes to get 4 + the original pokemon back (cloner keeps 1 copy). Total time: about 11 minutes. If you find a cloner patient enough to agree to 30 pokemon, that's roughly 30 minutes just in the trade. :-/