Btw, 24 notes a second is doing chromatics at 240bpm... Ain't that a lil' too high to set your goal ? I would set it around 200bpm (still, 20 notes/minute) or something so you wont get discouraged too much. Doing 24notes/second takes years of practise, imho. While doing 20 notes/second is much easier, but still hard. Once you're over 200bpm it gets more difficult to increase I think (haven't gone over 175 myself, so...) (I'm talking about strictly alternate picking here but, it's best you try some legato, taps... too)
Besides, like I said some time before. Music is an art, not math ! Nobody cares about how much notes you can play in one second, because they won't notice it anyway :) It's about how you keep your audience entertained !
Latz, Gul.