I believe I’ve isolated the main problem in playing this intro, and I think it’s the left hand. It just sort of runs out of steam after a few repetitions of this pattern. The way I see everyone playing it is alternating between the middle and pointer finger as shown in the photo. For some reason alternating between those two fingers and trying to “hop” over to the E string 13th fret with the same pointer finger to repeat the pattern is very fatiguing. I can sometimes manage to have enough stamina to repeat the entire cycle but it’s not effortless for sure.
Another solution I’ve come up with is alternating between the ring and middle fingers. This allows you to not have to “hop” over back to the 13th fret E string as your pointer finger could already be in place. And I feel this causes less fatigue as it more evenly uses all your fingers rather than putting all the loads on the pointer and middle, giving those fingers a resting period. The problem is it doesn’t feel physiologically correct to cycle between ring and middle finger. It has a very awkward feeling doing this. I also don’t see anyone doing this.
My current way for practicing this is to firstly play each of the 4, 16th note chunks by themselves as hammer-ons from nowhere, then picking the individual chunks, then the entire sequence as hammer-ons from nowhere, then picking the entire sequence. My main problem is the fatigue in my left hand, I have to skip the end of the chuck to keep the pattern synchronized with my right hand.
Any other things I could try to overcome this problem?