In my opinion, precise palm muting is crucial while sweep picking. That said, there's a lot of guitarists that excel using all different sorts of techniques, so maybe it's not required per se, but I think it helps immensely. The biggest advantage it gives in my mind, is that when ascending...
When sweep picking arpeggios, I've seen people roll barres to reach notes on the same fret, and I've also seen people squeezing their fingers one after the other onto the fret. This probably isn't a great description, so here's some tab. Rolling Barres: I - Index : M - Middle : R - Ring : P...
The best description I can think of is to keep your fingers like this picture, except you invert the first knuckle joint so that is points toward the palm, instead of away from the palm. This should reverse the angle of the pick with respect to the standard way of holding a pick.
Has anyone messed around with this? It's like holding the pick with the "OK" gesture, and inverting the thumb joint. It reverses the angle of the pick with relation to the standard style of holding a pick, with the pad of the thumb and side of the index finger. The Tuck and Patti article...