You don't have to draw 100 magics of everything if you can't be bothered, simply learn each gf's refine abilities and collect lots of M-stone peices, Magic stones and wizard stones then refine them for each magic. Yes it is also time consuming, but at least your characters and gf's will level up while you beat up the monsters

But chances are there will be a lot of magics in the game that you will not end up using. You don't probably won't need every character in the game to have 100 fires each or something like that, so don't bother drawing every single magic for every single person

Or just follow my other stratergy:
Buy lots of tents and refine them into curaga's using siren's life/cure refine ability.