So I'm working on my spider legs exercise, but I'm not sure if I should be paying attention to the fret board (where I'm placing my fingers) or if I should pay attention to which strings I'm strumming. Should I try to play without looking at the fret board to build my "muscle memory" for specific notes or should I play without looking where I'm strumming to build a memory when it comes to playing open strings/ignoring muted ones?