Yeah, I used to have a very similar strategy, and then I switched to just mashing down the right button and didnt seem to get any more or fewer double hits.
Mind you, I'd love it if for each attack there was exactly one attack that would do 2 damage and there was a subtle variation in the animation that would tell you which attack was the right one if you wanted to take the time to figure it out. I just have a hunch that that's not actually the way that battles were actually implemented