[Patashu]

Download Tachyon Alpha, Tachyon Beta, SSSC Pack, SSSC Pack 2 and Loaded Futurepack. They're packs focused around ultra fast streams, trills and jacks.

Most people's sweet spot is C600-C800. However, consider using a speedmod 10-25% as big with the distant mod on - it helps you combo but makes your MA worse.

If you want to get good at jacks, here's what you do: Find the jacky simfile for Sandstorm (in one of the HSMPs I believe, or get someone to hit you up), then play it over and over and over with failoff. Don't stop even when your wrists are burning, training jacking is about physically exhausting your wrists. When sandstorm feels too easy, do sandstorm 1.1x again with failoff. It will hurt, but after doing it every day for a week you'll be more consistent at jacks.