Well, I can tell you this: It's not the EV training (battling against the right pokémon) that's going to take a while. It's getting the right IVs. There's no such thing as IV training because a given pokémon's IVs are set in stone as much as its gender. You'll have to go through quite the truckload of Eevee to find six with the best IVs, so get ready to do an awful lot of breeding on Emerald Version (hello Flame Body, not to mention the fix on breeding that guarantees three inherited IVs.) Actually, come to think of it, I can see Ruby/Sapphire being more useful for breeding than Emerald in certain cases, because Ruby/Sapphire has the sandslide trick that Emerald's Match Call eviscerated with a rusty spoon. <==no estoy happy.