All good things come to those who practice . get yourself a metronome app and do this..
Find your max speed at 6 notes a click and push it up 3 BPM.
Then...
Do this for as long as you can and then return to your original BPM. Now thats easy.
Continue to push yourself faster and accurate with the metronome.
World Class is 120BPM triplets 6 notes a click!