I'm pretty good at sweeping arpeggios, but even though i practice with a metronome, my alternate picking just seems to have a forced/cramped sound to it. But then again, I dont practice nearly enough!
I love sweeping and string skipping, and your sweeps are great. I wasn't a huge fan of tapping as I was anti-VH for years, growing up in the 80's. I do some tapping, but use it sparingly. I am starting to incorporate tapped arpeggios and chords these days, for some different sounds and to develop new ideas.
Yes, speed and accuracy basically come from hour/days/weeks/months/years of wood shedding. The key to playing fast is watching your breathing to ensure you're not holding your breath, and playing as relaxed as possible, especially when playing long passages. I recently recorded a scratch track of Flight of Bumblebee for my band and it's a great song/exercise for practicing playing long alternate picked passages.
