Haha, I don't go to quite the extent of catching so many Pokemon and training them all, but I usually have about 10-12 that are ready to go at any time, that I switch in and out of my party as I see fit.
Also, if you're looking for the legendary beasts, it might be a good idea to have something that can either paralyze it or put it to sleep, too. Sure, they'll run away after the first turn, but every subsequent time you find them they'll still be affected by it, and I found that it made them a little bit easier to catch after that.