What is the most efficient way to fret adjacent strings in horizontal patterns?
For example, the 3rd and 4th notes of the A minor arpeggio in Example 6.1 of Gypsy Picking are both held by the first finger on the 7th fret. Should I fret each string one at a time with the fingertip, lifting my finger and moving it, or should I make a barre on the 7th fret?
There are a number of places where this option presents itself, the horizontal arpeggios being the most obvious example, so I'm wondering if there's a general preferred way.
I'm still working on the right-hand technique, so it's not a pressing question for me right now. But someday I'm going to be worrying about the fastest way to play this, so I might as well ask now.