Start slowly and try to get faster from time to time. But play it clean and concentrated, there is no use in playing damn fast but completely wrong :-)
Unfortunately with this program it sounds a little lousy, use it only to get the rough melodie and try to play it yourself then. You' ll see it' ll sound a lot better...
By the way; use a Plectrum or Tapping and you can do it a lot faster.
I only reached Tempo 150 for now (a friend of mine (Roland Hurni) did 200 on his Guitar!!), let me know how fast you can do...:-)
