But it worked at least once . I would still try it. And probably try different magnet and put it in centre of the buttons. Who knows. N3DSXL might just have a weird sensor that has a smaller radius? (probably not but still, you should try it)
Once out of like 100+ times, maybe 200. I've tried so many different magnets as well with the same results and I'm pretty darn sure I'm hitting the sweet spot. This bloody 3ds is just a massive arsehole.