I would recommend you try out Trigger's PC. Once you import your save over, it works like a pokebank, letting your transfer not just your pokemon between saves of all 3th gen games(RSE, FRLG, CL and GoD, as well as PokeBox), but also your items, money/coins, tutor moves via move reminder if you have the items required(heart scales or mushrooms) and so much more, even letting you evolve pokemon you can only get by trading, like machamp or gengar
As for even legendaries, the program will actually give you "rewards" for completing objectives or going far enough in the game, think of them like xbox achievements or playstation trophies. That includes tickets from all events and even the japanese only mew event(won't transfer to pokebank if you caught it outside of a japanese release tho). You even get some other event pokemon, if I recall correctly, like jiraichi and celebi.
So in short, don't bother, just download TRPC and let it do the work for you. I can't imagine playing gen 3 games without it anymore, as long as you have a GBA backup tool plus R4 Flashcart, you can even transfer saves from carts and get the event pokemon like that, it's amazing