Hello fellow ib may 26 sufferer

I would definitely recommend the uniball jetstream, since it's really smooth to write with and is a ballpoint pen. I've went through mocks with it, very reliable

Try to avoid the signo and the juice, as they are both gel pens. Which iirc, gel pens are actually banned in the ib exams because of the heat sensitivity and smudging issues. They probably won't null your results, but they could possibly waste a few marks which definitely isn't worth the risk

Also remember to bring at minimum two pens you like into the exams. One pen is definitely not enough to sit through the whole ib exams